diff --git a/OpenRA.Game/Network/UnitOrders.cs b/OpenRA.Game/Network/UnitOrders.cs
index 8f0c4a6bf5..74aabdce71 100755
--- a/OpenRA.Game/Network/UnitOrders.cs
+++ b/OpenRA.Game/Network/UnitOrders.cs
@@ -111,7 +111,11 @@ namespace OpenRA.Network
 				case "HandshakeRequest":
 					{
 						var request = HandshakeRequest.Deserialize(order.TargetString);
+						var localMods = orderManager.LobbyInfo.GlobalSettings.Mods.Select(m => "{0}@{1}".F(m,Mod.AllMods[m].Version)).ToArray();
 
+						// Check if mods match
+						if (localMods.FirstOrDefault().ToString().Split('@')[0] != request.Mods.FirstOrDefault().ToString().Split('@')[0])
+							throw new InvalidOperationException("Server's mod ({0}) and yours ({1}) don't match".F(localMods.FirstOrDefault().ToString().Split('@')[0], request.Mods.FirstOrDefault().ToString().Split('@')[0]));
 						// Check that the map exists on the client
 						if (!Game.modData.AvailableMaps.ContainsKey(request.Map))
 							throw new InvalidOperationException("Missing map {0}".F(request.Map));
@@ -126,7 +130,6 @@ namespace OpenRA.Network
 							State = Session.ClientState.NotReady
 						};
 
-						var localMods = orderManager.LobbyInfo.GlobalSettings.Mods.Select(m => "{0}@{1}".F(m,Mod.AllMods[m].Version)).ToArray();
 						var response = new HandshakeResponse()
 						{
 							Client = info,