diff --git a/README.md b/README.md
index 64aff73..172f51d 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 micro-ecc
 ==========
 
-A small ECDH and ECDSA implementation for 32-bit microcontrollers.
+A small ECDH and ECDSA implementation for 32-bit microcontrollers. See [ecc64](https://github.com/kmackay/ecc64) for a 64-bit implementation.
 
 Features
 --------