diff --git a/ChangeLog b/ChangeLog
index 976f88c449..6fb5c9308b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Mar  1 22:29:10 2011  Tanaka Akira  <akr@fsij.org>
+
+	* ext/openssl/ossl_pkey.h: parenthesize macro arguments.
+
 Tue Mar  1 22:02:35 2011  Shota Fukumori  <sorah@tubusu.net>
 
 	* lib/test/unit/parallel.rb: Fix number.
diff --git a/ext/openssl/ossl_pkey.h b/ext/openssl/ossl_pkey.h
index 67ff1fddd0..5e3329d326 100644
--- a/ext/openssl/ossl_pkey.h
+++ b/ext/openssl/ossl_pkey.h
@@ -21,21 +21,21 @@ extern ID id_private_q;
 #define OSSL_PKEY_IS_PRIVATE(obj)  (rb_iv_get((obj), "private") == Qtrue)
 
 #define WrapPKey(klass, obj, pkey) do { \
-    if (!pkey) { \
+    if (!(pkey)) { \
 	rb_raise(rb_eRuntimeError, "PKEY wasn't initialized!"); \
     } \
-    obj = Data_Wrap_Struct(klass, 0, EVP_PKEY_free, pkey); \
+    (obj) = Data_Wrap_Struct((klass), 0, EVP_PKEY_free, (pkey)); \
     OSSL_PKEY_SET_PUBLIC(obj); \
 } while (0)
 #define GetPKey(obj, pkey) do {\
-    Data_Get_Struct(obj, EVP_PKEY, pkey);\
-    if (!pkey) { \
+    Data_Get_Struct((obj), EVP_PKEY, (pkey));\
+    if (!(pkey)) { \
 	rb_raise(rb_eRuntimeError, "PKEY wasn't initialized!");\
     } \
 } while (0)
 #define SafeGetPKey(obj, pkey) do { \
-    OSSL_Check_Kind(obj, cPKey); \
-    GetPKey(obj, pkey); \
+    OSSL_Check_Kind((obj), cPKey); \
+    GetPKey((obj), (pkey)); \
 } while (0)
 
 void ossl_generate_cb(int, int, void *);
@@ -134,8 +134,8 @@ static VALUE ossl_##keytype##_set_##name(VALUE self, VALUE bignum)	\
 
 #define DEF_OSSL_PKEY_BN(class, keytype, name)				\
 do {									\
-	rb_define_method(class, #name, ossl_##keytype##_get_##name, 0);	\
-	rb_define_method(class, #name "=", ossl_##keytype##_set_##name, 1);\
+	rb_define_method((class), #name, ossl_##keytype##_get_##name, 0);	\
+	rb_define_method((class), #name "=", ossl_##keytype##_set_##name, 1);\
 } while (0)
 
 #endif /* _OSSL_PKEY_H_ */