diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index 01de5850471..a5e38943072 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -2819,7 +2819,7 @@ namespace ts {
                     return node.emitNode = { annotatedNodes: [node] } as EmitNode;
                 }
 
-                const sourceFile = getSourceFileOfNode(node);
+                const sourceFile = getSourceFileOfNode(getParseTreeNode(getSourceFileOfNode(node)));
                 getOrCreateEmitNode(sourceFile).annotatedNodes!.push(node);
             }
 
diff --git a/src/testRunner/unittests/transform.ts b/src/testRunner/unittests/transform.ts
index f219fb6c683..2fc4d117e99 100644
--- a/src/testRunner/unittests/transform.ts
+++ b/src/testRunner/unittests/transform.ts
@@ -400,6 +400,46 @@ namespace Foo {
                         }
                     }).outputText;
         });
+
+        // https://github.com/Microsoft/TypeScript/issues/24709
+        testBaseline("issue24709", () => {
+            const fs = vfs.createFromFileSystem(Harness.IO, /*caseSensitive*/ true);
+            const transformed = transform(createSourceFile("source.ts", "class X { echo(x: string) { return x; } }", ScriptTarget.ES3), [transformSourceFile]);
+            const transformedSourceFile = transformed.transformed[0];
+            transformed.dispose();
+            const host = new fakes.CompilerHost(fs);
+            host.getSourceFile = () => transformedSourceFile;
+            const program = createProgram(["source.ts"], {
+                  target: ScriptTarget.ES3,
+                  module: ModuleKind.None,
+                  noLib: true
+            }, host);
+            program.emit(transformedSourceFile, (_p, s, b) => host.writeFile("source.js", s, b));
+            return host.readFile("source.js")!.toString();
+
+            function transformSourceFile(context: TransformationContext) {
+                const visitor: Visitor = (node) => {
+                    if (isMethodDeclaration(node)) {
+                        return updateMethod(
+                          node,
+                          node.decorators,
+                          node.modifiers,
+                          node.asteriskToken,
+                          createIdentifier("foobar"),
+                          node.questionToken,
+                          node.typeParameters,
+                          node.parameters,
+                          node.type,
+                          node.body,
+                        );
+                      }
+                    return visitEachChild(node, visitor, context);
+                };
+                return (node: SourceFile) => visitNode(node, visitor);
+            }
+
+        });
+
     });
 }
 
diff --git a/tests/baselines/reference/transformApi/transformsCorrectly.issue24709.js b/tests/baselines/reference/transformApi/transformsCorrectly.issue24709.js
new file mode 100644
index 00000000000..9d1d48ca96d
--- /dev/null
+++ b/tests/baselines/reference/transformApi/transformsCorrectly.issue24709.js
@@ -0,0 +1,6 @@
+var X = /** @class */ (function () {
+    function X() {
+    }
+    X.prototype.foobar = function (x) { return x; };
+    return X;
+}());