diff --git a/README.md b/README.md
index 67587c99..47972f21 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,9 @@ complex web applications written entirely in Rust.
 
 The documentation is located at [http://hyperium.github.io/hyper](http://hyperium.github.io/hyper).
 
+___WARNING: Hyper is still under active development. The API is still changing
+in non-backwards-compatible ways without warning._
+
 ## Example
 
 Hello World Server: