diff --git a/php_memcached.c b/php_memcached.c
index 85c79901..50636952 100644
--- a/php_memcached.c
+++ b/php_memcached.c
@@ -3234,7 +3234,7 @@ static PHP_METHOD(Memcached, setOptions)
 	zval *options;
 	zend_bool ok = 1;
 	zend_string *key;
-	ulong key_index;
+	zend_ulong key_index;
 	zval *value;
 
 	MEMC_METHOD_INIT_VARS;