diff --git a/lib/6to5/modules/amd.js b/lib/6to5/modules/amd.js
index 6ffb6235ee..5ae4c44824 100644
--- a/lib/6to5/modules/amd.js
+++ b/lib/6to5/modules/amd.js
@@ -10,6 +10,8 @@ function AMDFormatter(file) {
   this.ids  = {};
 }
 
+util.inherits(AMDFormatter, CommonJSFormatter);
+
 AMDFormatter.prototype.transform = function (ast) {
   var program = ast.program;
   var body    = program.body;
@@ -76,8 +78,6 @@ AMDFormatter.prototype.importSpecifier = function (specifier, node, nodes) {
   ]));
 };
 
-AMDFormatter.prototype.export = CommonJSFormatter.prototype.export;
-
 AMDFormatter.prototype.exportSpecifier = function (specifier, node, nodes) {
   var variableName = util.getSpecifierName(specifier);
 
diff --git a/lib/6to5/modules/umd.js b/lib/6to5/modules/umd.js
new file mode 100644
index 0000000000..a9b4a02ca7
--- /dev/null
+++ b/lib/6to5/modules/umd.js
@@ -0,0 +1,48 @@
+module.exports = UMDFormatter;
+
+var CommonJSFormatter = require("./common");
+var AMDFormatter      = require("./amd");
+var util              = require("../util");
+var b                 = require("ast-types").builders;
+var _                 = require("lodash");
+
+function UMDFormatter(file) {
+  this.file = file;
+  this.ids  = {};
+}
+
+util.inherits(UMDFormatter, AMDFormatter);
+
+UMDFormatter.prototype.transform = function (ast) {
+  var program = ast.program;
+  var body    = program.body;
+
+  // build an array of module names
+
+  var names = [];
+  _.each(this.ids, function (id, name) {
+    names.push(b.literal(name));
+  });
+
+  // factory
+
+  var ids  = _.values(this.ids);
+  var args = [b.identifier("exports")].concat(ids);
+
+  var factory = b.functionExpression(null, args, b.blockStatement(body));
+
+  // runner
+
+  var runner = util.template("umd-runner-body", {
+    AMD_ARGUMENTS: b.arrayExpression([b.literal("exports")].concat(names)),
+
+    COMMON_ARGUMENTS: names.map(function (name) {
+      return b.callExpression(b.identifier("require"), [name])
+    })
+  });
+
+  //
+
+  var call = b.callExpression(runner, [b.thisExpression(), factory]);
+  program.body = [b.expressionStatement(call)];
+};
diff --git a/lib/6to5/templates/umd-runner-body.js b/lib/6to5/templates/umd-runner-body.js
new file mode 100644
index 0000000000..b78bb97cb6
--- /dev/null
+++ b/lib/6to5/templates/umd-runner-body.js
@@ -0,0 +1,7 @@
+(function (root, factory) {
+  if (typeof define === "function" && define.amd) {
+    define(AMD_ARGUMENTS, factory);
+  } else if (typeof exports !== "undefined") {
+    factory(exports, COMMON_ARGUMENTS);
+  }
+});
diff --git a/lib/6to5/transform.js b/lib/6to5/transform.js
index 24d78fdd29..1f3a3e96f3 100644
--- a/lib/6to5/transform.js
+++ b/lib/6to5/transform.js
@@ -106,7 +106,8 @@ transform.transformers = {
 
 transform.moduleFormatters = {
   common: require("./modules/common"),
-  amd:    require("./modules/amd")
+  amd:    require("./modules/amd"),
+  umd:    require("./modules/umd")
 };
 
 _.each(transform.transformers, function (transformer, key) {
diff --git a/lib/6to5/util.js b/lib/6to5/util.js
index c52ebe02d1..09cd30e33c 100644
--- a/lib/6to5/util.js
+++ b/lib/6to5/util.js
@@ -3,12 +3,15 @@ var astTypes = require("recast").types;
 var recast   = require("recast");
 var acorn    = require("acorn");
 var path     = require("path");
+var util     = require("util");
 var fs       = require("fs");
 var _        = require("lodash");
 
 var n = astTypes.namedTypes;
 var b = astTypes.builders;
 
+exports.inherits = util.inherits;
+
 exports.ensureBlock = function (node) {
   var block = node.body;
   if (block.type === "BlockStatement") return;
diff --git a/test/fixtures/syntax/modules-umd/exports-default/actual.js b/test/fixtures/syntax/modules-umd/exports-default/actual.js
new file mode 100644
index 0000000000..d7c96201d6
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/exports-default/actual.js
@@ -0,0 +1,8 @@
+export default 42;
+export default {};
+export default [];
+export default foo;
+export default function () {}
+export default class {}
+export default function foo () {}
+export default class foo {}
diff --git a/test/fixtures/syntax/modules-umd/exports-default/expected.js b/test/fixtures/syntax/modules-umd/exports-default/expected.js
new file mode 100644
index 0000000000..19c52b670d
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/exports-default/expected.js
@@ -0,0 +1,27 @@
+"use strict";
+
+(function (root, factory) {
+  if (typeof define === "function" && define.amd) {
+    define(["exports"], factory);
+  } else if (typeof exports !== "undefined") {
+    factory(exports);
+  }
+})(this, function (exports) {
+  exports.default = 42;
+  exports.default = {};
+  exports.default = [];
+  exports.default = foo;
+  exports.default = function() {};
+
+  exports.default = function() {
+    var _class = function() {};
+    return _class;
+  }();
+
+  exports.default = function foo() {};
+
+  exports.default = function() {
+    var foo = function foo() {};
+    return foo;
+  }();
+});
diff --git a/test/fixtures/syntax/modules-umd/exports-from/actual.js b/test/fixtures/syntax/modules-umd/exports-from/actual.js
new file mode 100644
index 0000000000..60857f6542
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/exports-from/actual.js
@@ -0,0 +1,6 @@
+export * from "foo";
+export {foo} from "foo";
+export {foo, bar} from "foo";
+export {foo as bar} from "foo";
+export {foo as default} from "foo";
+export {foo as default, bar} from "foo";
diff --git a/test/fixtures/syntax/modules-umd/exports-from/expected.js b/test/fixtures/syntax/modules-umd/exports-from/expected.js
new file mode 100644
index 0000000000..a9eac93074
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/exports-from/expected.js
@@ -0,0 +1,23 @@
+"use strict";
+
+(function (root, factory) {
+  if (typeof define === "function" && define.amd) {
+    define(["exports", "foo"], factory);
+  } else if (typeof exports !== "undefined") {
+    factory(exports, require("foo"));
+  }
+})(this, function (exports, _foo) {
+  (function(obj) {
+    for (var i in obj) {
+      exports[i] = obj[i];
+    }
+  })(_foo);
+
+  exports.foo = _foo.foo;
+  exports.foo = _foo.foo;
+  exports.bar = _foo.bar;
+  exports.bar = _foo.foo;
+  exports.default = _foo.foo;
+  exports.default = _foo.foo;
+  exports.bar = _foo.bar;
+});
diff --git a/test/fixtures/syntax/modules-umd/exports-named/actual.js b/test/fixtures/syntax/modules-umd/exports-named/actual.js
new file mode 100644
index 0000000000..8515ace759
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/exports-named/actual.js
@@ -0,0 +1,5 @@
+export {foo};
+export {foo, bar};
+export {foo as bar};
+export {foo as default};
+export {foo as default, bar};
diff --git a/test/fixtures/syntax/modules-umd/exports-named/expected.js b/test/fixtures/syntax/modules-umd/exports-named/expected.js
new file mode 100644
index 0000000000..8f40cd0dc3
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/exports-named/expected.js
@@ -0,0 +1,17 @@
+"use strict";
+
+(function (root, factory) {
+  if (typeof define === "function" && define.amd) {
+    define(["exports"], factory);
+  } else if (typeof exports !== "undefined") {
+    factory(exports);
+  }
+})(this, function (exports) {
+  exports.foo = foo;
+  exports.foo = foo;
+  exports.bar = bar;
+  exports.bar = foo;
+  exports.default = foo;
+  exports.default = foo;
+  exports.bar = bar;
+});
diff --git a/test/fixtures/syntax/modules-umd/exports-variable/actual.js b/test/fixtures/syntax/modules-umd/exports-variable/actual.js
new file mode 100644
index 0000000000..b4629cc731
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/exports-variable/actual.js
@@ -0,0 +1,8 @@
+export var foo = 1;
+export var foo2 = function () {};
+export var foo3;
+export let foo4 = 2;
+export let foo5;
+export const foo6 = 3;
+export function foo7 () {}
+export class foo8 {}
diff --git a/test/fixtures/syntax/modules-umd/exports-variable/expected.js b/test/fixtures/syntax/modules-umd/exports-variable/expected.js
new file mode 100644
index 0000000000..32c11d7a54
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/exports-variable/expected.js
@@ -0,0 +1,31 @@
+"use strict";
+
+(function (root, factory) {
+  if (typeof define === "function" && define.amd) {
+    define(["exports"], factory);
+  } else if (typeof exports !== "undefined") {
+    factory(exports);
+  }
+})(this, function (exports) {
+  exports.foo7 = foo7;
+  var foo = 1;
+  exports.foo = foo;
+  var foo2 = function() {};
+  exports.foo2 = foo2;
+  var foo3;
+  exports.foo3 = foo3;
+  var _foo4 = 2;
+  exports.foo4 = _foo4;
+  var _foo5;
+  exports.foo5 = _foo5;
+  var _foo6 = 3;
+  exports.foo6 = _foo6;
+  function foo7() {}
+
+  var foo8 = function() {
+    var foo8 = function foo8() {};
+    return foo8;
+  }();
+
+  exports.foo8 = foo8;
+});
diff --git a/test/fixtures/syntax/modules-umd/hoist-function-exports/actual.js b/test/fixtures/syntax/modules-umd/hoist-function-exports/actual.js
new file mode 100644
index 0000000000..aa0f9366ae
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/hoist-function-exports/actual.js
@@ -0,0 +1,11 @@
+import { isEven } from "./evens";
+
+export function nextOdd(n) {
+  return isEven(n) ? n + 1 : n + 2;
+}
+
+export var isOdd = (function(isEven) {
+  return function(n) {
+  return !isEven(n);
+  };
+})(isEven);
diff --git a/test/fixtures/syntax/modules-umd/hoist-function-exports/expected.js b/test/fixtures/syntax/modules-umd/hoist-function-exports/expected.js
new file mode 100644
index 0000000000..bac912b1f6
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/hoist-function-exports/expected.js
@@ -0,0 +1,24 @@
+"use strict";
+
+(function (root, factory) {
+  if (typeof define === "function" && define.amd) {
+    define(["exports", "./evens"], factory);
+  } else if (typeof exports !== "undefined") {
+    factory(exports, require("./evens"));
+  }
+})(this, function (exports, _evens) {
+  exports.nextOdd = nextOdd;
+  var isEven = _evens.isEven;
+
+  function nextOdd(n) {
+    return (isEven(n) ? n + 1 : n + 2);
+  }
+
+  var isOdd = function(isEven) {
+    return function(n) {
+      return !isEven(n);
+    };
+  }(isEven);
+
+  exports.isOdd = isOdd;
+});
diff --git a/test/fixtures/syntax/modules-umd/imports-default/actual.js b/test/fixtures/syntax/modules-umd/imports-default/actual.js
new file mode 100644
index 0000000000..e67418654c
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/imports-default/actual.js
@@ -0,0 +1,2 @@
+import foo from "foo";
+import {default as foo} from "foo";
diff --git a/test/fixtures/syntax/modules-umd/imports-default/expected.js b/test/fixtures/syntax/modules-umd/imports-default/expected.js
new file mode 100644
index 0000000000..6acee23c2b
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/imports-default/expected.js
@@ -0,0 +1,12 @@
+"use strict";
+
+(function (root, factory) {
+  if (typeof define === "function" && define.amd) {
+    define(["exports", "foo"], factory);
+  } else if (typeof exports !== "undefined") {
+    factory(exports, require("foo"));
+  }
+})(this, function (exports, _foo) {
+  var foo = _foo.default;
+  var foo = _foo.default;
+});
diff --git a/test/fixtures/syntax/modules-umd/imports-glob/actual.js b/test/fixtures/syntax/modules-umd/imports-glob/actual.js
new file mode 100644
index 0000000000..e55c077500
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/imports-glob/actual.js
@@ -0,0 +1 @@
+import * as foo from "foo";
diff --git a/test/fixtures/syntax/modules-umd/imports-glob/expected.js b/test/fixtures/syntax/modules-umd/imports-glob/expected.js
new file mode 100644
index 0000000000..fb5a921da1
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/imports-glob/expected.js
@@ -0,0 +1,11 @@
+"use strict";
+
+(function (root, factory) {
+  if (typeof define === "function" && define.amd) {
+    define(["exports", "foo"], factory);
+  } else if (typeof exports !== "undefined") {
+    factory(exports, require("foo"));
+  }
+})(this, function (exports, _foo) {
+  var foo = _foo;
+});
diff --git a/test/fixtures/syntax/modules-umd/imports-mixing/actual.js b/test/fixtures/syntax/modules-umd/imports-mixing/actual.js
new file mode 100644
index 0000000000..ef78c95b1c
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/imports-mixing/actual.js
@@ -0,0 +1 @@
+import foo, {baz as xyz} from "foo";
diff --git a/test/fixtures/syntax/modules-umd/imports-mixing/expected.js b/test/fixtures/syntax/modules-umd/imports-mixing/expected.js
new file mode 100644
index 0000000000..102bd20f80
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/imports-mixing/expected.js
@@ -0,0 +1,12 @@
+"use strict";
+
+(function (root, factory) {
+  if (typeof define === "function" && define.amd) {
+    define(["exports", "foo"], factory);
+  } else if (typeof exports !== "undefined") {
+    factory(exports, require("foo"));
+  }
+})(this, function (exports, _foo) {
+  var foo = _foo.default;
+  var xyz = _foo.baz;
+});
diff --git a/test/fixtures/syntax/modules-umd/imports-named/actual.js b/test/fixtures/syntax/modules-umd/imports-named/actual.js
new file mode 100644
index 0000000000..83a766c62d
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/imports-named/actual.js
@@ -0,0 +1,4 @@
+import {bar} from "foo";
+import {bar, baz} from "foo";
+import {bar as baz} from "foo";
+import {bar as baz, xyz} from "foo";
diff --git a/test/fixtures/syntax/modules-umd/imports-named/expected.js b/test/fixtures/syntax/modules-umd/imports-named/expected.js
new file mode 100644
index 0000000000..ed10909514
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/imports-named/expected.js
@@ -0,0 +1,16 @@
+"use strict";
+
+(function (root, factory) {
+  if (typeof define === "function" && define.amd) {
+    define(["exports", "foo"], factory);
+  } else if (typeof exports !== "undefined") {
+    factory(exports, require("foo"));
+  }
+})(this, function (exports, _foo) {
+  var bar = _foo.bar;
+  var bar = _foo.bar;
+  var baz = _foo.baz;
+  var baz = _foo.bar;
+  var baz = _foo.bar;
+  var xyz = _foo.xyz;
+});
diff --git a/test/fixtures/syntax/modules-umd/imports/actual.js b/test/fixtures/syntax/modules-umd/imports/actual.js
new file mode 100644
index 0000000000..222b6885ac
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/imports/actual.js
@@ -0,0 +1,3 @@
+import "foo";
+import "foo-bar";
+import "./directory/foo-bar";
diff --git a/test/fixtures/syntax/modules-umd/imports/expected.js b/test/fixtures/syntax/modules-umd/imports/expected.js
new file mode 100644
index 0000000000..656e51677d
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/imports/expected.js
@@ -0,0 +1,11 @@
+"use strict";
+
+(function (root, factory) {
+  if (typeof define === "function" && define.amd) {
+    define(["exports", "foo", "foo-bar", "./directory/foo-bar"], factory);
+  } else if (typeof exports !== "undefined") {
+    factory(exports, require("foo"), require("foo-bar"), require("./directory/foo-bar"));
+  }
+})(this, function (exports, _foo, _fooBar, _directoryFooBar) {
+
+});
diff --git a/test/fixtures/syntax/modules-umd/overview/actual.js b/test/fixtures/syntax/modules-umd/overview/actual.js
new file mode 100644
index 0000000000..a77d4d5dfa
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/overview/actual.js
@@ -0,0 +1,12 @@
+import "foo";
+import "foo-bar";
+import "./directory/foo-bar";
+import foo from "foo";
+import * as foo from "foo";
+import {bar} from "foo";
+import {foo as bar} from "foo";
+
+export {test};
+export var test = 5;
+
+export default test;
diff --git a/test/fixtures/syntax/modules-umd/overview/expected.js b/test/fixtures/syntax/modules-umd/overview/expected.js
new file mode 100644
index 0000000000..475ce88de8
--- /dev/null
+++ b/test/fixtures/syntax/modules-umd/overview/expected.js
@@ -0,0 +1,18 @@
+"use strict";
+
+(function (root, factory) {
+  if (typeof define === "function" && define.amd) {
+    define(["exports", "foo", "foo-bar", "./directory/foo-bar"], factory);
+  } else if (typeof exports !== "undefined") {
+    factory(exports, require("foo"), require("foo-bar"), require("./directory/foo-bar"));
+  }
+})(this, function (exports, _foo, _fooBar, _directoryFooBar) {
+  var foo = _foo.default;
+  var foo = _foo;
+  var bar = _foo.bar;
+  var bar = _foo.foo;
+  exports.test = test;
+  var test = 5;
+  exports.test = test;
+  exports.default = test;
+});