diff --git a/src/main.c b/src/main.c
index 2ff930a..6fb9e3f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -25,6 +25,7 @@
  */

 #include "config.h"
+#include <stdbool.h>
 #include "cfg_file.h"
 #include "rmilter.h"
 #include "util.h"