diff --git a/src/modules/uORB/uORB.h b/src/modules/uORB/uORB.h
index d4633c7d61..0035e0fd44 100644
--- a/src/modules/uORB/uORB.h
+++ b/src/modules/uORB/uORB.h
@@ -68,7 +68,7 @@ typedef const struct orb_metadata *orb_id_t;
  * Relevant for multi-topics / topic groups
  */
 enum ORB_PRIO {
-	ORB_PRIO_MIN = 0,
+	ORB_PRIO_MIN = 1, // leave 0 free for other purposes, eg. marking an uninitialized value
 	ORB_PRIO_VERY_LOW = 25,
 	ORB_PRIO_LOW = 50,
 	ORB_PRIO_DEFAULT = 75,