diff --git a/ChangeLog b/ChangeLog
index 6416630374..f3d65899a6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Jul 14 13:36:15 2008  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* ext/socket/extconf.rb: initialize winsock on win32 to avoid error
+	  dialog of OS.
+
 Mon Jul 14 06:02:26 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* lib/optparse.rb (OptionParser#environment): requires shellwords.
diff --git a/ext/socket/extconf.rb b/ext/socket/extconf.rb
index 0791714e49..7354a0f300 100644
--- a/ext/socket/extconf.rb
+++ b/ext/socket/extconf.rb
@@ -125,6 +125,11 @@ main()
   int passive, gaierr, inet4 = 0, inet6 = 0;
   struct addrinfo hints, *ai, *aitop;
   char straddr[INET6_ADDRSTRLEN], strport[16];
+#ifdef _WIN32
+  WSADATA retdata;
+
+  WSAStartup(MAKEWORD(2, 0), &retdata);
+#endif
 
   for (passive = 0; passive <= 1; passive++) {
     memset(&hints, 0, sizeof(hints));