diff --git a/README.md b/README.md
index 8fae2bc..aebca1a 100644
--- a/README.md
+++ b/README.md
@@ -293,6 +293,7 @@ There're also some great commercial libraries, like [amchart](http://www.amchart
 * [step](https://github.com/creationix/step/) - An async control-flow library that makes stepping through logic easy.
 * [contra](https://github.com/bevacqua/contra/) - Asynchronous flow control with a functional taste to it.
 * [Bluebird](https://github.com/petkaantonov/bluebird/) - fully featured promise library with focus on innovative features and performance.
+* [when](https://github.com/cujojs/when) - A solid, fast Promises/A+ and when() implementation, plus other async goodies.
 
 
 ## Routing