diff --git a/ebtree/ebmbtree.h b/ebtree/ebmbtree.h
index 947dd5e..12b534d 100644
--- a/ebtree/ebmbtree.h
+++ b/ebtree/ebmbtree.h
@@ -18,6 +18,9 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#ifndef _EBMBTREE_H
+#define _EBMBTREE_H
+
 #include <string.h>
 #include "ebtree.h"
 
@@ -334,3 +337,5 @@
 	return new;
 }
 
+#endif /* _EBMBTREE_H */
+