diff --git a/ChangeLog b/ChangeLog
index c0fda5c9..8e5af7a2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2008-05-26  Nicolas François  <nicolas.francois@centraliens.net>
+
+	* lib/groupio.h: Add protection against multiple inclusions.
+
 2008-05-26  Nicolas François  <nicolas.francois@centraliens.net>
 
 	* lib/pwio.h: Add protection against multiple inclusions.
diff --git a/lib/groupio.h b/lib/groupio.h
index 9f11d70f..ba708940 100644
--- a/lib/groupio.h
+++ b/lib/groupio.h
@@ -31,7 +31,12 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+/* $Id$ */
+#ifndef _GROUPIO_H
+#define _GROUPIO_H
+
 #include <grp.h>
+
 extern int gr_close (void);
 extern const struct group *gr_locate (const char *);
 extern const struct group *gr_locate_gid (gid_t gid);
@@ -45,3 +50,4 @@ extern int gr_unlock (void);
 extern int gr_update (const struct group *);
 extern int gr_sort (void);
 
+#endif