diff --git a/libguile/bdw-gc.h b/libguile/bdw-gc.h
index 2e1fce27b..7aa757fed 100644
--- a/libguile/bdw-gc.h
+++ b/libguile/bdw-gc.h
@@ -1,7 +1,7 @@
 #ifndef SCM_BDW_GC_H
 #define SCM_BDW_GC_H
 
-/* Copyright (C) 2006, 2008, 2009, 2011, 2012 Free Software Foundation, Inc.
+/* Copyright (C) 2006, 2008, 2009, 2011, 2012, 2013 Free Software Foundation, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public License
@@ -37,6 +37,11 @@
    routines.  */
 # define GC_NO_THREAD_REDIRECTS 1
 
+#ifdef __MINGW32__
+/* Rely on pthreads-w32.  */
+#define GC_WIN32_PTHREADS
+#endif
+
 #endif
 
 #include <gc/gc.h>