diff --git a/engine/common/cvar.c b/engine/common/cvar.c
index 17406d7a..e5744c9e 100644
--- a/engine/common/cvar.c
+++ b/engine/common/cvar.c
@@ -695,7 +695,11 @@ cvar_t *Cvar_SetCore (cvar_t *var, const char *value, qboolean force)
 	if (latch)
 	{
 		if (strcmp(latch, value))
+		{
 			var->modified++;	//only modified if it changed.
+			if (var->callback)
+				var->callback(var, latch);
+		}
 
 		Z_Free (latch);	// free the old value string
 	}
diff --git a/engine/common/cvar.h b/engine/common/cvar.h
index 2f01fe95..b5524a6e 100644
--- a/engine/common/cvar.h
+++ b/engine/common/cvar.h
@@ -67,12 +67,16 @@ typedef struct cvar_s
 	//free style :)
 	char		*name2;
 
+	void		(*callback) (struct cvar_s *var, char *oldvalue);
+
 	char		*defaultstr;	//default
 	qbyte		restriction;
 } cvar_t;
 
-#define FCVAR(ConsoleName,ConsoleName2,Value,Flags) {ConsoleName, Value, NULL, Flags, 0, 0, 0, ConsoleName2}
+#define FCVARC(ConsoleName,ConsoleName2,Value,Flags,Callback) {ConsoleName, Value, NULL, Flags, 0, 0, 0, ConsoleName2, Callback}
+#define FCVAR(ConsoleName,ConsoleName2,Value,Flags) FCVARC(ConsoleName, ConsoleName2, Value, Flags, NULL)
 #define SCVARF(ConsoleName,Value, Flags) FCVAR(ConsoleName, NULL, Value, Flags)
+#define SCVARC(ConsoleName,Value,Callback) FCVARC(ConsoleName, NULL, Value, 0, Callback)
 #define SCVAR(ConsoleName,Value) FCVAR(ConsoleName, NULL, Value, 0)
 
 typedef struct cvar_group_s