diff --git a/object/types.proto b/object/types.proto
index cdfe6d2..3fea559 100644
--- a/object/types.proto
+++ b/object/types.proto
@@ -133,6 +133,12 @@ message Header {
 
     // List of identifiers of the objects generated by splitting current one.
     repeated neo.fs.v2.refs.ObjectID children = 5 [json_name = "children"];
+
+    // 16 byte UUID used to identify the split object hierarchy parts. Must be
+    // unique inside container. All objects participaiting in the split must
+    // have the same `split_id` value.
+    bytes split_id = 6 [json_name = "splitID"];
+
   }
   // Position of the object in the split hierarchy
   Split split = 11 [json_name = "split"];