diff --git a/axum/src/routing/mod.rs b/axum/src/routing/mod.rs
index ee64c37ef7..13d6be7bfe 100644
--- a/axum/src/routing/mod.rs
+++ b/axum/src/routing/mod.rs
@@ -688,4 +688,5 @@ impl<S, B> fmt::Debug for Endpoint<S, B> {
 fn traits() {
     use crate::test_helpers::*;
     assert_send::<Router<(), ()>>();
+    assert_sync::<Router<(), ()>>();
 }
diff --git a/axum/src/routing/service.rs b/axum/src/routing/service.rs
index bcf9ee3bca..c604f69c0e 100644
--- a/axum/src/routing/service.rs
+++ b/axum/src/routing/service.rs
@@ -163,3 +163,10 @@ where
         }
     }
 }
+
+#[test]
+#[allow(warnings)]
+fn traits() {
+    use crate::test_helpers::*;
+    assert_sync::<RouterService<()>>();
+}