diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 86b2b78b3f4..c1e85fa09fe 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -552,7 +552,11 @@ module ts {
             }
 
             function emitLines(nodes: Node[]) {
-                for (var i = 0; i < nodes.length; i++) {
+                emitLinesStartingAt(nodes, /*startIndex*/ 0);
+            }
+
+            function emitLinesStartingAt(nodes: Node[], startIndex: number): void {
+                for (var i = startIndex; i < nodes.length; i++) {
                     writeLine();
                     emit(nodes[i]);
                 }
@@ -1594,7 +1598,7 @@ module ts {
                 });
             }
 
-            function emitAMDModule(node: SourceFile) {
+            function emitAMDModule(node: SourceFile, startIndex: number) {
                 var imports = getExternalImportDeclarations(node);
                 writeLine();
                 write("define([\"require\", \"exports\"");
@@ -1615,7 +1619,7 @@ module ts {
                 write(") {");
                 increaseIndent();
                 emitCaptureThisForNodeIfNecessary(node);
-                emitLines(node.statements);
+                emitLinesStartingAt(node.statements, startIndex);
                 var exportName = resolver.getExportAssignmentName(node);
                 if (exportName) {
                     writeLine();
@@ -1633,9 +1637,9 @@ module ts {
                 write("});");
             }
 
-            function emitCommonJSModule(node: SourceFile) {
+            function emitCommonJSModule(node: SourceFile, startIndex: number) {
                 emitCaptureThisForNodeIfNecessary(node);
-                emitLines(node.statements);
+                emitLinesStartingAt(node.statements, startIndex);
                 var exportName = resolver.getExportAssignmentName(node);
                 if (exportName) {
                     writeLine();
@@ -1650,8 +1654,25 @@ module ts {
                 }
             }
 
+            function isDirectivePrologue(n: Statement): boolean {
+                return n.kind === SyntaxKind.ExpressionStatement && (<ExpressionStatement>n).expression.kind === SyntaxKind.StringLiteral;
+            }
+
             function emitSourceFile(node: SourceFile) {
                 currentSourceFile = node;
+                var startIndex = 0;
+                for (; startIndex < node.statements.length; ++startIndex) {
+                    // emit prologue directives prior to __extends
+                    if (isDirectivePrologue(node.statements[startIndex])) {
+                        if (startIndex > 0) {
+                            writeLine();
+                        }
+                        emit(node.statements[startIndex]);
+                    }
+                    else {
+                        break;
+                    }
+                }
                 if (!extendsEmitted && resolver.getNodeCheckFlags(node) & NodeCheckFlags.EmitExtends) {
                     writeLine();
                     write("var __extends = this.__extends || function (d, b) {");
@@ -1671,15 +1692,15 @@ module ts {
                 }
                 if (node.flags & NodeFlags.ExternalModule) {
                     if (compilerOptions.module === ModuleKind.AMD) {
-                        emitAMDModule(node);
+                        emitAMDModule(node, startIndex);
                     }
                     else {
-                        emitCommonJSModule(node);
+                        emitCommonJSModule(node, startIndex);
                     }
                 }
                 else {
                     emitCaptureThisForNodeIfNecessary(node);
-                    emitLines(node.statements);
+                    emitLinesStartingAt(node.statements, startIndex);
                 }
             }
 
diff --git a/tests/baselines/reference/strictMode1.js b/tests/baselines/reference/strictMode1.js
index 14bba3aa4a3..f4c9db50ab7 100644
--- a/tests/baselines/reference/strictMode1.js
+++ b/tests/baselines/reference/strictMode1.js
@@ -4,13 +4,13 @@ class A {}
 class B extends A {}
 
 //// [strictMode1.js]
+"use strict";
 var __extends = this.__extends || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
     __.prototype = b.prototype;
     d.prototype = new __();
 };
-"use strict";
 var A = (function () {
     function A() {
     }
diff --git a/tests/baselines/reference/strictMode3.js b/tests/baselines/reference/strictMode3.js
index 39d55dffd14..792ab931f53 100644
--- a/tests/baselines/reference/strictMode3.js
+++ b/tests/baselines/reference/strictMode3.js
@@ -12,13 +12,13 @@ function foo() {
 }
 
 //// [strictMode3.js]
+"use strict";
 var __extends = this.__extends || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
     __.prototype = b.prototype;
     d.prototype = new __();
 };
-"use strict";
 var A = (function () {
     function A() {
     }
diff --git a/tests/baselines/reference/strictMode5.js b/tests/baselines/reference/strictMode5.js
new file mode 100644
index 00000000000..8a3ff76fe04
--- /dev/null
+++ b/tests/baselines/reference/strictMode5.js
@@ -0,0 +1,46 @@
+//// [strictMode5.ts]
+function foo(...args) {
+    "use strict"
+}
+
+class A {
+    m() {
+        "use strict"
+
+        var v = () => {
+            return this.n();
+        };
+    }
+    n() {}
+}
+
+function bar(x: number = 10) {
+    "use strict"
+}
+
+//// [strictMode5.js]
+function foo() {
+    var args = [];
+    for (var _i = 0; _i < arguments.length; _i++) {
+        args[_i - 0] = arguments[_i];
+    }
+    "use strict";
+}
+var A = (function () {
+    function A() {
+    }
+    A.prototype.m = function () {
+        var _this = this;
+        "use strict";
+        var v = function () {
+            return _this.n();
+        };
+    };
+    A.prototype.n = function () {
+    };
+    return A;
+})();
+function bar(x) {
+    if (x === void 0) { x = 10; }
+    "use strict";
+}
diff --git a/tests/cases/compiler/strictMode5.ts b/tests/cases/compiler/strictMode5.ts
new file mode 100644
index 00000000000..c980cf7c86d
--- /dev/null
+++ b/tests/cases/compiler/strictMode5.ts
@@ -0,0 +1,18 @@
+function foo(...args) {
+    "use strict"
+}
+
+class A {
+    m() {
+        "use strict"
+
+        var v = () => {
+            return this.n();
+        };
+    }
+    n() {}
+}
+
+function bar(x: number = 10) {
+    "use strict"
+}
\ No newline at end of file