diff --git a/ChangeLog b/ChangeLog
index a9a09bd876..b1afd63407 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Dec 27 20:54:22 2015  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* process.c: use rb_w32_uchdir() instead of plain chdir() on Windows.
+	  reported by naruse via twitter.
+
 Sun Dec 27 20:00:31 2015  SHIBATA Hiroshi  <hsbt@ruby-lang.org>
 
 	* enc/x_emoji.h: fix dead-link.
diff --git a/process.c b/process.c
index 0df7607fd7..e2ecceb438 100644
--- a/process.c
+++ b/process.c
@@ -2967,6 +2967,11 @@ save_env(struct rb_execarg *sargp)
 }
 #endif
 
+#ifdef _WIN32
+#undef chdir
+#define chdir(p) rb_w32_uchdir(p)
+#endif
+
 /* This function should be async-signal-safe when sargp is NULL.  Hopefully it is. */
 int
 rb_execarg_run_options(const struct rb_execarg *eargp, struct rb_execarg *sargp, char *errmsg, size_t errmsg_buflen)