Overtime wages is calculated on the basis of the wages prevailing at the time of overtime. However, if the new salary introduced has retrospective effect, say with effect from December 2007, then an employee is eligible for back wages and that should include the OT wages and, therefore, in such cases OT shall also be calculated at the revised rates. On the other hand, if the revision has effect from Jan 08 only, then OT for Dec 07 will be calculated at the pre revised wage rate only. Remember, this is applicable only for OT and for leave encashment, payment of Gratuity and Retrenchment benefits the rate applicable at the time of such leave encashment or payment of gratuity/ compensation will be taken as the base. Regards, Madhu.T.K