diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 132213f950a..4849cb8c89e 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -1158,6 +1158,7 @@ module ts {
         }
 
         function internIdentifier(text: string): string {
+            text = escapeIdentifier(text);
             return hasProperty(identifiers, text) ? identifiers[text] : (identifiers[text] = text);
         }
 
@@ -1168,8 +1169,7 @@ module ts {
             identifierCount++;
             if (isIdentifier) {
                 var node = <Identifier>createNode(SyntaxKind.Identifier);
-                var text = escapeIdentifier(scanner.getTokenValue());
-                node.text = internIdentifier(text);
+                node.text = internIdentifier(scanner.getTokenValue());
                 nextToken();
                 return finishNode(node);
             }
diff --git a/tests/baselines/reference/escapedReservedCompilerNamedIdentifier.js b/tests/baselines/reference/escapedReservedCompilerNamedIdentifier.js
new file mode 100644
index 00000000000..e2a8471be0a
--- /dev/null
+++ b/tests/baselines/reference/escapedReservedCompilerNamedIdentifier.js
@@ -0,0 +1,93 @@
+//// [escapedReservedCompilerNamedIdentifier.ts]
+// double underscores
+var __proto__ = 10;
+var o = {
+    "__proto__": 0
+};
+var b = o["__proto__"];
+var o1 = {
+    __proto__: 0
+};
+var b1 = o1["__proto__"];
+// Triple underscores
+var ___proto__ = 10;
+var o2 = {
+    "___proto__": 0
+};
+var b2 = o2["___proto__"];
+var o3 = {
+    ___proto__: 0
+};
+var b3 = o3["___proto__"];
+// One underscore
+var _proto__ = 10;
+var o4 = {
+    "_proto__": 0
+};
+var b4 = o4["_proto__"];
+var o5 = {
+    _proto__: 0
+};
+var b5 = o5["_proto__"];
+
+//// [escapedReservedCompilerNamedIdentifier.js]
+// double underscores
+var __proto__ = 10;
+var o = {
+    "__proto__": 0
+};
+var b = o["__proto__"];
+var o1 = {
+    __proto__: 0
+};
+var b1 = o1["__proto__"];
+// Triple underscores
+var ___proto__ = 10;
+var o2 = {
+    "___proto__": 0
+};
+var b2 = o2["___proto__"];
+var o3 = {
+    ___proto__: 0
+};
+var b3 = o3["___proto__"];
+// One underscore
+var _proto__ = 10;
+var o4 = {
+    "_proto__": 0
+};
+var b4 = o4["_proto__"];
+var o5 = {
+    _proto__: 0
+};
+var b5 = o5["_proto__"];
+
+
+//// [escapedReservedCompilerNamedIdentifier.d.ts]
+declare var __proto__: number;
+declare var o: {
+    "__proto__": number;
+};
+declare var b: number;
+declare var o1: {
+    __proto__: number;
+};
+declare var b1: number;
+declare var ___proto__: number;
+declare var o2: {
+    "___proto__": number;
+};
+declare var b2: number;
+declare var o3: {
+    ___proto__: number;
+};
+declare var b3: number;
+declare var _proto__: number;
+declare var o4: {
+    "_proto__": number;
+};
+declare var b4: number;
+declare var o5: {
+    _proto__: number;
+};
+declare var b5: number;
diff --git a/tests/baselines/reference/escapedReservedCompilerNamedIdentifier.types b/tests/baselines/reference/escapedReservedCompilerNamedIdentifier.types
new file mode 100644
index 00000000000..f54c7b80757
--- /dev/null
+++ b/tests/baselines/reference/escapedReservedCompilerNamedIdentifier.types
@@ -0,0 +1,85 @@
+=== tests/cases/compiler/escapedReservedCompilerNamedIdentifier.ts ===
+// double underscores
+var __proto__ = 10;
+>__proto__ : number
+
+var o = {
+>o : { "__proto__": number; }
+>{    "__proto__": 0} : { "__proto__": number; }
+
+    "__proto__": 0
+};
+var b = o["__proto__"];
+>b : number
+>o["__proto__"] : number
+>o : { "__proto__": number; }
+
+var o1 = {
+>o1 : { __proto__: number; }
+>{    __proto__: 0} : { __proto__: number; }
+
+    __proto__: 0
+>__proto__ : number
+
+};
+var b1 = o1["__proto__"];
+>b1 : number
+>o1["__proto__"] : number
+>o1 : { __proto__: number; }
+
+// Triple underscores
+var ___proto__ = 10;
+>___proto__ : number
+
+var o2 = {
+>o2 : { "___proto__": number; }
+>{    "___proto__": 0} : { "___proto__": number; }
+
+    "___proto__": 0
+};
+var b2 = o2["___proto__"];
+>b2 : number
+>o2["___proto__"] : number
+>o2 : { "___proto__": number; }
+
+var o3 = {
+>o3 : { ___proto__: number; }
+>{    ___proto__: 0} : { ___proto__: number; }
+
+    ___proto__: 0
+>___proto__ : number
+
+};
+var b3 = o3["___proto__"];
+>b3 : number
+>o3["___proto__"] : number
+>o3 : { ___proto__: number; }
+
+// One underscore
+var _proto__ = 10;
+>_proto__ : number
+
+var o4 = {
+>o4 : { "_proto__": number; }
+>{    "_proto__": 0} : { "_proto__": number; }
+
+    "_proto__": 0
+};
+var b4 = o4["_proto__"];
+>b4 : number
+>o4["_proto__"] : number
+>o4 : { "_proto__": number; }
+
+var o5 = {
+>o5 : { _proto__: number; }
+>{    _proto__: 0} : { _proto__: number; }
+
+    _proto__: 0
+>_proto__ : number
+
+};
+var b5 = o5["_proto__"];
+>b5 : number
+>o5["_proto__"] : number
+>o5 : { _proto__: number; }
+
diff --git a/tests/baselines/reference/protoAsIndexInIndexExpression.types b/tests/baselines/reference/protoAsIndexInIndexExpression.types
index e950098e6a1..bde87801fa5 100644
--- a/tests/baselines/reference/protoAsIndexInIndexExpression.types
+++ b/tests/baselines/reference/protoAsIndexInIndexExpression.types
@@ -20,8 +20,8 @@ WorkspacePrototype['__proto__'] = EntityPrototype;
 >EntityPrototype : any
 
 var o = {
->o : {}
->{    "__proto__": 0} : {}
+>o : { "__proto__": number; }
+>{    "__proto__": 0} : { "__proto__": number; }
 
     "__proto__": 0
 };
diff --git a/tests/cases/compiler/escapedReservedCompilerNamedIdentifier.ts b/tests/cases/compiler/escapedReservedCompilerNamedIdentifier.ts
new file mode 100644
index 00000000000..da874acf73a
--- /dev/null
+++ b/tests/cases/compiler/escapedReservedCompilerNamedIdentifier.ts
@@ -0,0 +1,31 @@
+//@declaration: true
+// double underscores
+var __proto__ = 10;
+var o = {
+    "__proto__": 0
+};
+var b = o["__proto__"];
+var o1 = {
+    __proto__: 0
+};
+var b1 = o1["__proto__"];
+// Triple underscores
+var ___proto__ = 10;
+var o2 = {
+    "___proto__": 0
+};
+var b2 = o2["___proto__"];
+var o3 = {
+    ___proto__: 0
+};
+var b3 = o3["___proto__"];
+// One underscore
+var _proto__ = 10;
+var o4 = {
+    "_proto__": 0
+};
+var b4 = o4["_proto__"];
+var o5 = {
+    _proto__: 0
+};
+var b5 = o5["_proto__"];
\ No newline at end of file