diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 9a41b4a89ae..a857c8f60fd 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4950,6 +4950,7 @@ module ts {
             if (fullTypeCheck) {
                 checkCollisionWithCapturedSuperVariable(node, node.name);
                 checkCollisionWithCapturedThisVariable(node, node.name);
+                checkCollistionWithRequireExportsInGeneratedCode(node, node.name);
                 checkCollisionWithArgumentsInGeneratedCode(node);
                 if (program.getCompilerOptions().noImplicitAny && !node.type) {
                     switch (node.kind) {
@@ -5692,6 +5693,24 @@ module ts {
             }
         }
 
+        function checkCollistionWithRequireExportsInGeneratedCode(node: Node, name: Identifier) {
+            if (!needCollisionCheckForIdentifier(node, name, "require") && !needCollisionCheckForIdentifier(node, name, "exports")) {
+                return;
+            }
+
+            // Uninstantiated modules shouldnt do this check
+            if (node.kind === SyntaxKind.ModuleDeclaration && !isInstantiated(node)) {
+                return;
+            }
+
+            // In case of variable declaration, node.parent is variable statement so look at the variable statement's parent
+            var parent = node.kind === SyntaxKind.VariableDeclaration ? node.parent.parent : node.parent;
+            if (parent.kind === SyntaxKind.SourceFile && isExternalModule(<SourceFile>parent)) {
+                // If the declaration happens to be in external module, report error that require and exports are reserved keywords
+                error(name, Diagnostics.Duplicate_identifier_0_Compiler_reserves_name_1_in_top_level_scope_of_an_external_module, name.text, name.text);
+            }
+        }
+
         function checkVariableDeclaration(node: VariableDeclaration) {
             checkSourceElement(node.type);
             checkExportsOnMergedDeclarations(node);
@@ -5719,6 +5738,7 @@ module ts {
 
                 checkCollisionWithCapturedSuperVariable(node, node.name);
                 checkCollisionWithCapturedThisVariable(node, node.name);
+                checkCollistionWithRequireExportsInGeneratedCode(node, node.name);
                 if (!useTypeFromValueDeclaration) {
                     // TypeScript 1.0 spec (April 2014): 5.1
                     // Multiple declarations for the same variable name in the same declaration space are permitted,
@@ -5988,6 +6008,7 @@ module ts {
             checkTypeNameIsReserved(node.name, Diagnostics.Class_name_cannot_be_0);
             checkTypeParameters(node.typeParameters);
             checkCollisionWithCapturedThisVariable(node, node.name);
+            checkCollistionWithRequireExportsInGeneratedCode(node, node.name);
             checkExportsOnMergedDeclarations(node);
             var symbol = getSymbolOfNode(node);
             var type = <InterfaceType>getDeclaredTypeOfSymbol(symbol);
@@ -6203,6 +6224,7 @@ module ts {
             }
             checkTypeNameIsReserved(node.name, Diagnostics.Enum_name_cannot_be_0);
             checkCollisionWithCapturedThisVariable(node, node.name);
+            checkCollistionWithRequireExportsInGeneratedCode(node, node.name);
             checkExportsOnMergedDeclarations(node);
             var enumSymbol = getSymbolOfNode(node);
             var enumType = getDeclaredTypeOfSymbol(enumSymbol);
@@ -6276,6 +6298,7 @@ module ts {
         function checkModuleDeclaration(node: ModuleDeclaration) {
             if (fullTypeCheck) {
                 checkCollisionWithCapturedThisVariable(node, node.name);
+                checkCollistionWithRequireExportsInGeneratedCode(node, node.name);
                 checkExportsOnMergedDeclarations(node);
                 var symbol = getSymbolOfNode(node);
                 if (symbol.flags & SymbolFlags.ValueModule && symbol.declarations.length > 1 && !isInAmbientContext(node)) {
@@ -6310,6 +6333,7 @@ module ts {
 
         function checkImportDeclaration(node: ImportDeclaration) {
             checkCollisionWithCapturedThisVariable(node, node.name);
+            checkCollistionWithRequireExportsInGeneratedCode(node, node.name);
             var symbol = getSymbolOfNode(node);
             var target: Symbol;
             
diff --git a/src/compiler/diagnosticInformationMap.generated.ts b/src/compiler/diagnosticInformationMap.generated.ts
index 14360f39314..aa1b793f6ac 100644
--- a/src/compiler/diagnosticInformationMap.generated.ts
+++ b/src/compiler/diagnosticInformationMap.generated.ts
@@ -253,6 +253,7 @@ module ts {
         Import_name_cannot_be_0: { code: 2438, category: DiagnosticCategory.Error, key: "Import name cannot be '{0}'" },
         Import_declaration_in_an_ambient_external_module_declaration_cannot_reference_external_module_through_relative_external_module_name: { code: 2439, category: DiagnosticCategory.Error, key: "Import declaration in an ambient external module declaration cannot reference external module through relative external module name." },
         Import_declaration_conflicts_with_local_declaration_of_0: { code: 2440, category: DiagnosticCategory.Error, key: "Import declaration conflicts with local declaration of '{0}'" },
+        Duplicate_identifier_0_Compiler_reserves_name_1_in_top_level_scope_of_an_external_module: { code: 2441, category: DiagnosticCategory.Error, key: "Duplicate identifier '{0}'. Compiler reserves name '{1}' in top level scope of an external module." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: DiagnosticCategory.Error, key: "Import declaration '{0}' is using private name '{1}'." },
         Type_parameter_0_of_exported_class_has_or_is_using_name_1_from_private_module_2: { code: 4001, category: DiagnosticCategory.Error, key: "Type parameter '{0}' of exported class has or is using name '{1}' from private module '{2}'." },
         Type_parameter_0_of_exported_class_has_or_is_using_private_name_1: { code: 4002, category: DiagnosticCategory.Error, key: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index adceb133a93..eef8da8c857 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1004,6 +1004,11 @@
         "category": "Error",
         "code": 2440
     },
+    "Duplicate identifier '{0}'. Compiler reserves name '{1}' in top level scope of an external module.": {
+        "category": "Error",
+        "code": 2441
+    },
+
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
diff --git a/tests/baselines/reference/collisionExportsRequireAndAlias.errors.txt b/tests/baselines/reference/collisionExportsRequireAndAlias.errors.txt
new file mode 100644
index 00000000000..2ed2ee5d10e
--- /dev/null
+++ b/tests/baselines/reference/collisionExportsRequireAndAlias.errors.txt
@@ -0,0 +1,20 @@
+==== tests/cases/compiler/collisionExportsRequireAndAlias_file2.ts (2 errors) ====
+    import require = require('collisionExportsRequireAndAlias_file1'); // Error
+           ~~~~~~~
+!!! Duplicate identifier 'require'. Compiler reserves name 'require' in top level scope of an external module.
+    import exports = require('collisionExportsRequireAndAlias_file3333'); // Error
+           ~~~~~~~
+!!! Duplicate identifier 'exports'. Compiler reserves name 'exports' in top level scope of an external module.
+    export function foo() {
+        require.bar();
+    }
+    export function foo2() {
+        exports.bar2();
+    }
+==== tests/cases/compiler/collisionExportsRequireAndAlias_file1.ts (0 errors) ====
+    export function bar() {
+    }
+    
+==== tests/cases/compiler/collisionExportsRequireAndAlias_file3333.ts (0 errors) ====
+    export function bar2() {
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/collisionExportsRequireAndAlias.js b/tests/baselines/reference/collisionExportsRequireAndAlias.js
index 83f23accccf..2e4210f4910 100644
--- a/tests/baselines/reference/collisionExportsRequireAndAlias.js
+++ b/tests/baselines/reference/collisionExportsRequireAndAlias.js
@@ -1,23 +1,42 @@
-//// [collisionExportsRequireAndAlias.ts]
-// TODO: re-enable, fails when run in the browser with full compiler suite, but not when run alone
-
-////@module: amd
-//// @Filename: collisionExportsRequireAndAlias_file1.ts
-//export function bar() {
-//}
-
-//// @Filename: collisionExportsRequireAndAlias_file3333.ts
-//export function bar2() {
-//}
-//// @Filename: collisionExportsRequireAndAlias_file2.ts
-//import require = require('collisionExportsRequireAndAlias_file1'); // Error
-//import exports = require('collisionExportsRequireAndAlias_file3333'); // Error
-//export function foo() {
-//    require.bar();
-//}
-//export function foo2() {
-//    exports.bar2();
-//}
+//// [tests/cases/compiler/collisionExportsRequireAndAlias.ts] ////
 
-//// [collisionExportsRequireAndAlias.js]
-// TODO: re-enable, fails when run in the browser with full compiler suite, but not when run alone
+//// [collisionExportsRequireAndAlias_file1.ts]
+export function bar() {
+}
+
+//// [collisionExportsRequireAndAlias_file3333.ts]
+export function bar2() {
+}
+//// [collisionExportsRequireAndAlias_file2.ts]
+import require = require('collisionExportsRequireAndAlias_file1'); // Error
+import exports = require('collisionExportsRequireAndAlias_file3333'); // Error
+export function foo() {
+    require.bar();
+}
+export function foo2() {
+    exports.bar2();
+}
+
+//// [collisionExportsRequireAndAlias_file1.js]
+define(["require", "exports"], function (require, exports) {
+    function bar() {
+    }
+    exports.bar = bar;
+});
+//// [collisionExportsRequireAndAlias_file3333.js]
+define(["require", "exports"], function (require, exports) {
+    function bar2() {
+    }
+    exports.bar2 = bar2;
+});
+//// [collisionExportsRequireAndAlias_file2.js]
+define(["require", "exports", 'collisionExportsRequireAndAlias_file1', 'collisionExportsRequireAndAlias_file3333'], function (require, exports, require, exports) {
+    function foo() {
+        require.bar();
+    }
+    exports.foo = foo;
+    function foo2() {
+        exports.bar2();
+    }
+    exports.foo2 = foo2;
+});
diff --git a/tests/baselines/reference/collisionExportsRequireAndAlias.types b/tests/baselines/reference/collisionExportsRequireAndAlias.types
deleted file mode 100644
index 0e13caf3247..00000000000
--- a/tests/baselines/reference/collisionExportsRequireAndAlias.types
+++ /dev/null
@@ -1,21 +0,0 @@
-=== tests/cases/compiler/collisionExportsRequireAndAlias.ts ===
-// TODO: re-enable, fails when run in the browser with full compiler suite, but not when run alone
-No type information for this code.
-No type information for this code.////@module: amd
-No type information for this code.//// @Filename: collisionExportsRequireAndAlias_file1.ts
-No type information for this code.//export function bar() {
-No type information for this code.//}
-No type information for this code.
-No type information for this code.//// @Filename: collisionExportsRequireAndAlias_file3333.ts
-No type information for this code.//export function bar2() {
-No type information for this code.//}
-No type information for this code.//// @Filename: collisionExportsRequireAndAlias_file2.ts
-No type information for this code.//import require = require('collisionExportsRequireAndAlias_file1'); // Error
-No type information for this code.//import exports = require('collisionExportsRequireAndAlias_file3333'); // Error
-No type information for this code.//export function foo() {
-No type information for this code.//    require.bar();
-No type information for this code.//}
-No type information for this code.//export function foo2() {
-No type information for this code.//    exports.bar2();
-No type information for this code.//}
-No type information for this code.
\ No newline at end of file
diff --git a/tests/baselines/reference/collisionExportsRequireAndClass.errors.txt b/tests/baselines/reference/collisionExportsRequireAndClass.errors.txt
new file mode 100644
index 00000000000..9b90ab50c11
--- /dev/null
+++ b/tests/baselines/reference/collisionExportsRequireAndClass.errors.txt
@@ -0,0 +1,10 @@
+==== tests/cases/compiler/collisionExportsRequireAndClass.ts (2 errors) ====
+    export class require {
+                 ~~~~~~~
+!!! Duplicate identifier 'require'. Compiler reserves name 'require' in top level scope of an external module.
+    }
+    export class exports {
+                 ~~~~~~~
+!!! Duplicate identifier 'exports'. Compiler reserves name 'exports' in top level scope of an external module.
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/collisionExportsRequireAndClass.types b/tests/baselines/reference/collisionExportsRequireAndClass.types
deleted file mode 100644
index 07debc40147..00000000000
--- a/tests/baselines/reference/collisionExportsRequireAndClass.types
+++ /dev/null
@@ -1,8 +0,0 @@
-=== tests/cases/compiler/collisionExportsRequireAndClass.ts ===
-export class require {
->require : require
-}
-export class exports {
->exports : exports
-}
-
diff --git a/tests/baselines/reference/collisionExportsRequireAndEnum.errors.txt b/tests/baselines/reference/collisionExportsRequireAndEnum.errors.txt
new file mode 100644
index 00000000000..0ecd5edef83
--- /dev/null
+++ b/tests/baselines/reference/collisionExportsRequireAndEnum.errors.txt
@@ -0,0 +1,13 @@
+==== tests/cases/compiler/collisionExportsRequireAndEnum.ts (2 errors) ====
+    export enum require { // Error
+                ~~~~~~~
+!!! Duplicate identifier 'require'. Compiler reserves name 'require' in top level scope of an external module.
+        _thisVal1,
+        _thisVal2,
+    }
+    export enum exports { // Error
+                ~~~~~~~
+!!! Duplicate identifier 'exports'. Compiler reserves name 'exports' in top level scope of an external module.
+        _thisVal1,
+        _thisVal2,
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/collisionExportsRequireAndEnum.types b/tests/baselines/reference/collisionExportsRequireAndEnum.types
deleted file mode 100644
index b347b72284b..00000000000
--- a/tests/baselines/reference/collisionExportsRequireAndEnum.types
+++ /dev/null
@@ -1,19 +0,0 @@
-=== tests/cases/compiler/collisionExportsRequireAndEnum.ts ===
-export enum require { // Error
->require : require
-
-    _thisVal1,
->_thisVal1 : require
-
-    _thisVal2,
->_thisVal2 : require
-}
-export enum exports { // Error
->exports : exports
-
-    _thisVal1,
->_thisVal1 : exports
-
-    _thisVal2,
->_thisVal2 : exports
-}
diff --git a/tests/baselines/reference/collisionExportsRequireAndFunction.errors.txt b/tests/baselines/reference/collisionExportsRequireAndFunction.errors.txt
new file mode 100644
index 00000000000..bf35c4ce334
--- /dev/null
+++ b/tests/baselines/reference/collisionExportsRequireAndFunction.errors.txt
@@ -0,0 +1,12 @@
+==== tests/cases/compiler/collisionExportsRequireAndFunction.ts (2 errors) ====
+    export function exports() {
+                    ~~~~~~~
+!!! Duplicate identifier 'exports'. Compiler reserves name 'exports' in top level scope of an external module.
+        return 1;
+    }
+    export function require() {
+                    ~~~~~~~
+!!! Duplicate identifier 'require'. Compiler reserves name 'require' in top level scope of an external module.
+        return "require";
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/collisionExportsRequireAndFunction.types b/tests/baselines/reference/collisionExportsRequireAndFunction.types
deleted file mode 100644
index 8b90397c6fe..00000000000
--- a/tests/baselines/reference/collisionExportsRequireAndFunction.types
+++ /dev/null
@@ -1,12 +0,0 @@
-=== tests/cases/compiler/collisionExportsRequireAndFunction.ts ===
-export function exports() {
->exports : () => number
-
-    return 1;
-}
-export function require() {
->require : () => string
-
-    return "require";
-}
-
diff --git a/tests/baselines/reference/collisionExportsRequireAndModule.errors.txt b/tests/baselines/reference/collisionExportsRequireAndModule.errors.txt
new file mode 100644
index 00000000000..1fe42767adb
--- /dev/null
+++ b/tests/baselines/reference/collisionExportsRequireAndModule.errors.txt
@@ -0,0 +1,23 @@
+==== tests/cases/compiler/collisionExportsRequireAndModule.ts (2 errors) ====
+    export module require {
+                  ~~~~~~~
+!!! Duplicate identifier 'require'. Compiler reserves name 'require' in top level scope of an external module.
+        export interface I {
+        }
+        export class C {
+        }
+    }
+    export function foo(): require.I {
+        return null;
+    }
+    export module exports {
+                  ~~~~~~~
+!!! Duplicate identifier 'exports'. Compiler reserves name 'exports' in top level scope of an external module.
+        export interface I {
+        }
+        export class C {
+        }
+    }
+    export function foo2(): exports.I {
+        return null;
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/collisionExportsRequireAndModule.types b/tests/baselines/reference/collisionExportsRequireAndModule.types
deleted file mode 100644
index c462a508d06..00000000000
--- a/tests/baselines/reference/collisionExportsRequireAndModule.types
+++ /dev/null
@@ -1,35 +0,0 @@
-=== tests/cases/compiler/collisionExportsRequireAndModule.ts ===
-export module require {
->require : typeof require
-
-    export interface I {
->I : I
-    }
-    export class C {
->C : C
-    }
-}
-export function foo(): require.I {
->foo : () => require.I
->require : unknown
->I : require.I
-
-    return null;
-}
-export module exports {
->exports : typeof exports
-
-    export interface I {
->I : I
-    }
-    export class C {
->C : C
-    }
-}
-export function foo2(): exports.I {
->foo2 : () => exports.I
->exports : unknown
->I : exports.I
-
-    return null;
-}
diff --git a/tests/baselines/reference/collisionExportsRequireAndVar.errors.txt b/tests/baselines/reference/collisionExportsRequireAndVar.errors.txt
new file mode 100644
index 00000000000..127a40f0f0b
--- /dev/null
+++ b/tests/baselines/reference/collisionExportsRequireAndVar.errors.txt
@@ -0,0 +1,10 @@
+==== tests/cases/compiler/collisionExportsRequireAndVar.ts (2 errors) ====
+    export function foo() {
+    }
+    var exports = 1;
+        ~~~~~~~
+!!! Duplicate identifier 'exports'. Compiler reserves name 'exports' in top level scope of an external module.
+    var require = "require";
+        ~~~~~~~
+!!! Duplicate identifier 'require'. Compiler reserves name 'require' in top level scope of an external module.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/collisionExportsRequireAndVar.types b/tests/baselines/reference/collisionExportsRequireAndVar.types
deleted file mode 100644
index 656c705aa23..00000000000
--- a/tests/baselines/reference/collisionExportsRequireAndVar.types
+++ /dev/null
@@ -1,10 +0,0 @@
-=== tests/cases/compiler/collisionExportsRequireAndVar.ts ===
-export function foo() {
->foo : () => void
-}
-var exports = 1;
->exports : number
-
-var require = "require";
->require : string
-
diff --git a/tests/cases/compiler/collisionExportsRequireAndAlias.ts b/tests/cases/compiler/collisionExportsRequireAndAlias.ts
index 4c249d83a0c..b79da28f66b 100644
--- a/tests/cases/compiler/collisionExportsRequireAndAlias.ts
+++ b/tests/cases/compiler/collisionExportsRequireAndAlias.ts
@@ -1,19 +1,17 @@
-// TODO: re-enable, fails when run in the browser with full compiler suite, but not when run alone
+//@module: amd
+// @Filename: collisionExportsRequireAndAlias_file1.ts
+export function bar() {
+}
 
-////@module: amd
-//// @Filename: collisionExportsRequireAndAlias_file1.ts
-//export function bar() {
-//}
-
-//// @Filename: collisionExportsRequireAndAlias_file3333.ts
-//export function bar2() {
-//}
-//// @Filename: collisionExportsRequireAndAlias_file2.ts
-//import require = require('collisionExportsRequireAndAlias_file1'); // Error
-//import exports = require('collisionExportsRequireAndAlias_file3333'); // Error
-//export function foo() {
-//    require.bar();
-//}
-//export function foo2() {
-//    exports.bar2();
-//}
\ No newline at end of file
+// @Filename: collisionExportsRequireAndAlias_file3333.ts
+export function bar2() {
+}
+// @Filename: collisionExportsRequireAndAlias_file2.ts
+import require = require('collisionExportsRequireAndAlias_file1'); // Error
+import exports = require('collisionExportsRequireAndAlias_file3333'); // Error
+export function foo() {
+    require.bar();
+}
+export function foo2() {
+    exports.bar2();
+}
\ No newline at end of file