diff --git a/src/SlashCommands.js b/src/SlashCommands.js
index 3de3943b9e..ba4b08c3d0 100644
--- a/src/SlashCommands.js
+++ b/src/SlashCommands.js
@@ -117,8 +117,7 @@ var commands = {
                     return reject("Usage: /join #alias:domain");
                 }
                 if (!room_alias.match(/:/)) {
-                    var domain = MatrixClientPeg.get().credentials.userId.replace(/^.*:/, '');
-                    room_alias += ':' + domain;
+                    room_alias += ':' + MatrixClientPeg.get().getDomain();
                 }
 
                 // Try to find a room with this alias
@@ -164,8 +163,7 @@ var commands = {
                     return reject("Usage: /part [#alias:domain]");
                 }
                 if (!room_alias.match(/:/)) {
-                    var domain = MatrixClientPeg.get().credentials.userId.replace(/^.*:/, '');
-                    room_alias += ':' + domain;
+                    room_alias += ':' + MatrixClientPeg.get().getDomain();
                 }
 
                 // Try to find a room with this alias
diff --git a/src/components/structures/CreateRoom.js b/src/components/structures/CreateRoom.js
index c21bc80c6b..116202d324 100644
--- a/src/components/structures/CreateRoom.js
+++ b/src/components/structures/CreateRoom.js
@@ -251,7 +251,7 @@ module.exports = React.createClass({
             var UserSelector = sdk.getComponent("elements.UserSelector");
             var RoomHeader = sdk.getComponent("rooms.RoomHeader");
 
-            var domain = MatrixClientPeg.get().credentials.userId.replace(/^.*:/, '');
+            var domain = MatrixClientPeg.get().getDomain();
 
             return (
             <div className="mx_CreateRoom">