diff --git a/requirements-dev.txt b/requirements-dev.txt
index 0908d9ca3b..2702e1f43a 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -7,3 +7,4 @@ py-geth>=0.5.0
 https://github.com/ethereum/pyethereum/tarball/b06829e56e2a3de5276077a611ed8813b6cf5e74
 secp256k1>=0.12.0
 rlp==0.4.6
+hypothesis==3.4.2