diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c
index c886a9dc7298..616c0b80195c 100644
--- a/cmd/zdb/zdb.c
+++ b/cmd/zdb/zdb.c
@@ -1434,6 +1434,11 @@ dump_deadlist(dsl_deadlist_t *dl)
 	if (dump_opt['d'] < 3)
 		return;
 
+	if (dl->dl_oldfmt) {
+		dump_bpobj(&dl->dl_bpobj, "old-format deadlist", 0);
+		return;
+	}
+
 	zdb_nicenum(dl->dl_phys->dl_used, bytes);
 	zdb_nicenum(dl->dl_phys->dl_comp, comp);
 	zdb_nicenum(dl->dl_phys->dl_uncomp, uncomp);