diff --git a/python/pyspark/mllib/classification.py b/python/pyspark/mllib/classification.py
index 9e28dfbb9145d..2bbb9c3fca315 100644
--- a/python/pyspark/mllib/classification.py
+++ b/python/pyspark/mllib/classification.py
@@ -66,7 +66,8 @@ def predict(self, x):
         if margin > 0:
             prob = 1 / (1 + exp(-margin))
         else:
-            prob = 1 - 1 / (1 + exp(margin))
+            exp_margin = exp(margin)
+            prob = exp_margin / (1 + exp_margin)
         return 1 if prob > 0.5 else 0