diff --git a/book/changelog.md b/book/changelog.md
index 3f12e7d0..d552c3fa 100644
--- a/book/changelog.md
+++ b/book/changelog.md
@@ -153,6 +153,8 @@ This will be the first release of Grapevine since it was forked from Conduit
 14. Use trust-dns for all DNS queries, instead of only for SRV records and SRV
     record targets in server discovery.
     ([!156](https://gitlab.computer.surgery/matrix/grapevine/-/merge_requests/156))
+15. Return an error on when attempting to delete a nonexistent local alias.
+    ([!186](https://gitlab.computer.surgery/matrix/grapevine/-/merge_requests/186))
 
 ### Fixed
 
diff --git a/src/api/client_server/alias.rs b/src/api/client_server/alias.rs
index b2fbcf65..5ec165f5 100644
--- a/src/api/client_server/alias.rs
+++ b/src/api/client_server/alias.rs
@@ -75,6 +75,13 @@ pub(crate) async fn delete_alias_route(
         ));
     }
 
+    if services().rooms.alias.resolve_local_alias(&body.room_alias)?.is_none() {
+        return Err(Error::BadRequest(
+            ErrorKind::NotFound,
+            "Alias is not assigned.",
+        ));
+    }
+
     if let Some(info) = &body.appservice_info {
         if !info.aliases.is_match(body.room_alias.as_str()) {
             return Err(Error::BadRequest(