diff --git a/homeassistant/components/transmission/__init__.py b/homeassistant/components/transmission/__init__.py
index b50f228ddad..e0ced70f15e 100644
--- a/homeassistant/components/transmission/__init__.py
+++ b/homeassistant/components/transmission/__init__.py
@@ -91,7 +91,8 @@ TRANS_SCHEMA = vol.All(
 )
 
 CONFIG_SCHEMA = vol.Schema(
-    {DOMAIN: vol.All(cv.ensure_list, [TRANS_SCHEMA])}, extra=vol.ALLOW_EXTRA
+    vol.All(cv.deprecated(DOMAIN), {DOMAIN: vol.All(cv.ensure_list, [TRANS_SCHEMA])}),
+    extra=vol.ALLOW_EXTRA,
 )
 
 PLATFORMS = ["sensor", "switch"]