diff --git a/libs/freetdm/src/zap_wanpipe.c b/libs/freetdm/src/zap_wanpipe.c
index 7b5fabfd3d..fef68ab584 100644
--- a/libs/freetdm/src/zap_wanpipe.c
+++ b/libs/freetdm/src/zap_wanpipe.c
@@ -503,7 +503,7 @@ zap_status_t wanpipe_init(zap_software_interface_t **zint)
 
 zap_status_t wanpipe_destroy(void)
 {
-	int i,j;
+	unsigned int i,j;
 
 	for(i = 1; i <= wanpipe_interface.span_index; i++) {
 		zap_span_t *cur_span = &wanpipe_interface.spans[i];