diff --git a/Modules/stropmodule.c b/Modules/stropmodule.c
index 1821db8..e9e9039 100644
--- a/Modules/stropmodule.c
+++ b/Modules/stropmodule.c
@@ -349,7 +349,7 @@
 	if (i < 0)
 		i = 0;
 
-	if (n == 0)
+	if (n == 0 && i <= last)
 		return PyInt_FromLong((long)i);
 
 	last -= n;
@@ -394,7 +394,7 @@
 	if (i < 0)
 		i = 0;
 
-	if (n == 0)
+	if (n == 0 && i <= last)
 		return PyInt_FromLong((long)last);
 
 	for (j = last-n; j >= i; --j)