diff --git a/tox.ini b/tox.ini
index 6098716d..b737cdf5 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,10 +4,7 @@ minversion = 1.6
 skipsdist = True
 
 [testenv]
-# Set PYTHONHASHSEED to 0 so that randomisation is disabled and
-# urlutils.urlencode() has predictable results.
 setenv = VIRTUAL_ENV={envdir}
-        PYTHONHASHSEED=0
 usedevelop = True
 install_command = pip install -U {opts} {packages}
 deps = -r{toxinidir}/requirements.txt