diff --git a/builtin/providers/heroku/resource_heroku_domain.go b/builtin/providers/heroku/resource_heroku_domain.go
index df5c87e33..6f00fdf55 100644
--- a/builtin/providers/heroku/resource_heroku_domain.go
+++ b/builtin/providers/heroku/resource_heroku_domain.go
@@ -97,7 +97,9 @@ func resource_heroku_domain_diff(
 			"app":      diff.AttrTypeCreate,
 		},
 
-		ComputedAttrs: []string{},
+		ComputedAttrs: []string{
+			"cname",
+		},
 	}
 
 	return b.Diff(s, c)