diff --git a/builtin-fsck.c b/builtin-fsck.c
index 7321ab236b6925ef12f9e169b130eb53428d81a5..727310afc2327726dd87f5ad6438cd28c07810c9 100644
--- a/builtin-fsck.c
+++ b/builtin-fsck.c
@@ -397,6 +397,8 @@ static int fsck_commit(struct commit *commit)
 {
 	char *buffer = commit->buffer;
 	unsigned char tree_sha1[20], sha1[20];
+	struct commit_graft *graft;
+	int parents = 0;
 
 	if (verbose)
 		fprintf(stderr, "Checking commit %s\n",
@@ -411,6 +413,28 @@ static int fsck_commit(struct commit *commit)
 		if (get_sha1_hex(buffer+7, sha1) || buffer[47] != '\n')
 			return objerror(&commit->object, "invalid 'parent' line format - bad sha1");
 		buffer += 48;
+		parents++;
+	}
+	graft = lookup_commit_graft(commit->object.sha1);
+	if (graft) {
+		struct commit_list *p = commit->parents;
+		parents = 0;
+		while (p) {
+			p = p->next;
+			parents++;
+		}
+		if (graft->nr_parent == -1 && !parents)
+			; /* shallow commit */
+		else if (graft->nr_parent != parents)
+			return objerror(&commit->object, "graft objects missing");
+	} else {
+		struct commit_list *p = commit->parents;
+		while (p && parents) {
+			p = p->next;
+			parents--;
+		}
+		if (p || parents)
+			return objerror(&commit->object, "parent objects missing");
 	}
 	if (memcmp(buffer, "author ", 7))
 		return objerror(&commit->object, "invalid format - expected 'author' line");
diff --git a/commit.c b/commit.c
index 6684c4e73113f50f046c6541af8f2142751dea5b..94d5b3d2618d335585084170ef6a3a8e67f34c62 100644
--- a/commit.c
+++ b/commit.c
@@ -193,7 +193,7 @@ static void prepare_commit_graft(void)
 	commit_graft_prepared = 1;
 }
 
-static struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
+struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 {
 	int pos;
 	prepare_commit_graft();
diff --git a/commit.h b/commit.h
index 10e2b5d4cfdc7ac129ead711421ccc51d2667f02..3ad3dd9af17215e2fb12c215911a863be573d50f 100644
--- a/commit.h
+++ b/commit.h
@@ -101,6 +101,7 @@ struct commit_graft {
 struct commit_graft *read_graft_line(char *buf, int len);
 int register_commit_graft(struct commit_graft *, int);
 int read_graft_file(const char *graft_file);
+struct commit_graft *lookup_commit_graft(const unsigned char *sha1);
 
 extern struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2, int cleanup);