diff --git a/baselines/ddpg/ddpg_learner.py b/baselines/ddpg/ddpg_learner.py
index 3fc8a77..9058334 100755
--- a/baselines/ddpg/ddpg_learner.py
+++ b/baselines/ddpg/ddpg_learner.py
@@ -17,7 +17,7 @@ except ImportError:
 def normalize(x, stats):
     if stats is None:
         return x
-    return (x - stats.mean) / stats.std
+    return (x - stats.mean) / (stats.std + 1e-8)
 
 
 def denormalize(x, stats):