diff --git a/lib/6to5/transformation/transform.js b/lib/6to5/transformation/transform.js
index 74079d5d0b..9d32b62fa9 100644
--- a/lib/6to5/transformation/transform.js
+++ b/lib/6to5/transformation/transform.js
@@ -95,6 +95,7 @@ _.each({
 
   typeofSymbol:              require("./transformers/optional-typeof-symbol"),
   coreAliasing:              require("./transformers/optional-core-aliasing"),
+  externalRegenerator:       require("./transformers/optional-external-regenerator-runtime"),
   undefinedToVoid:           require("./transformers/optional-undefined-to-void"),
 
   // spec
diff --git a/lib/6to5/transformation/transformers/optional-external-regenerator-runtime.js b/lib/6to5/transformation/transformers/optional-external-regenerator-runtime.js
new file mode 100644
index 0000000000..9294a6c76e
--- /dev/null
+++ b/lib/6to5/transformation/transformers/optional-external-regenerator-runtime.js
@@ -0,0 +1,16 @@
+var t = require("../../types");
+
+exports.optional = true;
+
+exports.ast = {
+  enter: function (ast, file) {
+    file._regeneratorId = file.addImport("regenerator/runtime-module", "regeneratorRuntime");
+  }
+};
+
+exports.MemberExpression = function (node, parent, scope, context, file) {
+  var obj = node.object;
+  var prop = node.property;
+  if (!t.isReferenced(node, parent) || !t.isReferenced(obj, node)) return;
+  if (obj.name === "regeneratorRuntime") return t.memberExpression(file._regeneratorId, prop);
+};