diff --git a/tox.ini b/tox.ini
--- a/tox.ini
+++ b/tox.ini
@@ -2,6 +2,8 @@
 envlist = py{26,27}-{pytest,nose}
 
 [testenv]
+setenv =
+    PYTHONHASHSEED = 0
 deps =
     nose: nose
     pytest: pytest