diff --git a/shallow.c b/shallow.c
index 68dd10687b81d238ae9a5a99a61acf4e1396b668..5f626c013890b60c991200434589425a0e16cef9 100644
--- a/shallow.c
+++ b/shallow.c
@@ -153,6 +153,8 @@ static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 {
 	struct write_shallow_data *data = cb_data;
 	const char *hex = sha1_to_hex(graft->sha1);
+	if (graft->nr_parent != -1)
+		return 0;
 	data->count++;
 	if (data->use_pack_protocol)
 		packet_buf_write(data->out, "shallow %s", hex);