diff --git a/README.md b/README.md
index 2ca3e6f..ddfbee0 100644
--- a/README.md
+++ b/README.md
@@ -43,7 +43,7 @@ Alternatively, if you are directly using the library as a browser embed:
 
 ## Compatibility
 
-While `fastTimeout` is based on `postMessage`, it automatically falls back to `setImmediate` in environments where that function is defined. Hence, you can transparently use it in Node.js as well.
+While `fastTimeout` is based on `postMessage`, it automatically falls back to `setImmediate` in environments where that function is defined. Hence, you can transparently use it in Node.js as well. In environments where neither `postMessage` nor `setImmediate` is defined, it falls back to plain `setTimeout`; you get a performance degradation in that case, but at least your code will still work.
 
 ## Reference
 
diff --git a/src/fastTimeout.js b/src/fastTimeout.js
index 908e925..6659922 100644
--- a/src/fastTimeout.js
+++ b/src/fastTimeout.js
@@ -40,5 +40,6 @@ function enable() {
 }
 
 var hasSetImmediate = (typeof setImmediate === 'function');
+var hasPostMessage = (typeof self.postMessage === 'function');
 
-export default hasSetImmediate ? setImmediate : enable();
+export default hasPostMessage ? enable() : hasSetImmediate ? setImmediate : _.defer;