diff --git a/winsup/mingw/ChangeLog b/winsup/mingw/ChangeLog
index d08ffe5b7..5fc2e9a71 100644
--- a/winsup/mingw/ChangeLog
+++ b/winsup/mingw/ChangeLog
@@ -1,3 +1,9 @@
+2005-08-10  Danny Smith  <dannysmith@users.sourceforge.net>
+
+	* include/wctype.h (towupper, towlower): Change arg and return value
+	types to wint_t.
+	* include/ctype.h (towupper, towlower): Likewise.
+
 2005-08-10  Danny Smith  <dannysmith@users.sourceforge.net>
 
 	* mthr_stub.c (__mingwthr_key_dtor): Replace assert(0) with 
diff --git a/winsup/mingw/include/ctype.h b/winsup/mingw/include/ctype.h
index 1c321b603..f4020afdf 100644
--- a/winsup/mingw/include/ctype.h
+++ b/winsup/mingw/include/ctype.h
@@ -187,8 +187,11 @@ _CRTIMP int __cdecl iswspace(wint_t);
 _CRTIMP int __cdecl iswupper(wint_t);
 _CRTIMP int __cdecl iswxdigit(wint_t);
 
-_CRTIMP wchar_t __cdecl towlower(wchar_t);
-_CRTIMP wchar_t __cdecl towupper(wchar_t);
+/* Older MS docs uses wchar_t for arg and return type, while newer
+   online MS docs say arg is wint_t and return is int.
+   ISO C uses wint_t for both.  */
+_CRTIMP wint_t __cdecl towlower (wint_t);
+_CRTIMP wint_t __cdecl towupper (wint_t);
 
 _CRTIMP int __cdecl isleadbyte (int);
 
diff --git a/winsup/mingw/include/wctype.h b/winsup/mingw/include/wctype.h
index 533163e04..ed8f05f77 100644
--- a/winsup/mingw/include/wctype.h
+++ b/winsup/mingw/include/wctype.h
@@ -79,8 +79,11 @@ _CRTIMP int __cdecl	iswspace(wint_t);
 _CRTIMP int __cdecl	iswupper(wint_t);
 _CRTIMP int __cdecl	iswxdigit(wint_t);
 
-_CRTIMP wchar_t __cdecl	towlower(wchar_t);
-_CRTIMP wchar_t __cdecl	towupper(wchar_t);
+/* Older MS docs uses wchar_t for arg and return type, while newer
+   online MS docs say arg is wint_t and return is int.
+   ISO C uses wint_t for both.  */
+_CRTIMP wint_t __cdecl	towlower (wint_t);
+_CRTIMP wint_t __cdecl	towupper (wint_t);
 
 _CRTIMP int __cdecl	isleadbyte (int);