diff --git a/ChangeLog b/ChangeLog
index 9f6d6adb9b..1729d8948b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Aug 27 04:03:18 2011  Koichi Sasada  <ko1@atdot.net>
+
+	* iseq.c (iseq_data_to_ary): fix type of variable
+	  (long -> unsigned long) to suppress a warning.
+
 Sat Aug 27 04:02:11 2011  Koichi Sasada  <ko1@atdot.net>
 
 	* vm_core.h: add a decl. of rb_autoloading_value().
diff --git a/iseq.c b/iseq.c
index bd7be02c4f..b636ae0942 100644
--- a/iseq.c
+++ b/iseq.c
@@ -1101,7 +1101,8 @@ cdhash_each(VALUE key, VALUE value, VALUE ary)
 static VALUE
 iseq_data_to_ary(rb_iseq_t *iseq)
 {
-    long i, pos, ti;
+    long i, ti;
+    unsigned int pos;
     unsigned int line = 0;
     VALUE *seq;