diff --git a/ChangeLog b/ChangeLog
index f1b24cf6db..55023b6dbb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Sep  7 15:54:58 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ruby_atomic.h (ATOMIC_VALUE_CAS): fix typo.
+	  TODO: make arguments of all CAS macros consistent.
+
 Sun Sep  6 16:07:22 2015  Eric Wong  <e@80x24.org>
 
 	* ccan/list/list.h: suppress unused argument warnings
diff --git a/ruby_atomic.h b/ruby_atomic.h
index cd2fbcea50..57368a7448 100644
--- a/ruby_atomic.h
+++ b/ruby_atomic.h
@@ -168,7 +168,7 @@ ruby_atomic_size_exchange(size_t *ptr, size_t val)
 #   define ATOMIC_VALUE_EXCHANGE(var, val) ATOMIC_EXCHANGE(var, val)
 # endif
 # ifndef ATOMIC_VALUE_CAS
-#   define ATOMIC_VALUE_CAS(var, oldval, val) ATOMIC_CAS(var, oldval, newval)
+#   define ATOMIC_VALUE_CAS(var, oldval, val) ATOMIC_CAS(var, oldval, val)
 # endif
 #endif