diff --git a/src/g_game.cpp b/src/g_game.cpp
index 485980a48..e8af5cf80 100644
--- a/src/g_game.cpp
+++ b/src/g_game.cpp
@@ -208,7 +208,10 @@ CVAR (Float,	m_forward,		1.f,	CVAR_GLOBALCONFIG|CVAR_ARCHIVE)
 CVAR (Float,	m_side,			2.f,	CVAR_GLOBALCONFIG|CVAR_ARCHIVE)
  
 int 			turnheld;								// for accelerative turning 
- 
+
+EXTERN_CVAR (Bool, invertmouse)
+EXTERN_CVAR (Bool, invertmousex)
+
 // mouse values are used once 
 float 			mousex;
 float 			mousey; 		
@@ -1035,9 +1038,23 @@ bool G_Responder (event_t *ev)
 		break;
 
 	// [RH] mouse buttons are sent as key up/down events
-	case EV_Mouse: 
-		mousex = ev->x;
-		mousey = ev->y;
+	case EV_Mouse:
+        if(invertmousex)
+        {
+		   mousex = -ev->x;
+        }
+        else
+        {
+            mousex = ev->x;
+        }
+        if(invertmouse)
+        {
+            mousey = -ev->y;
+        }
+        else
+        {
+            mousey = ev->y;
+        }
 		break;
 	}