A constant lumen output control system for providing a constant lumen output throughout the life of a lamp at the mean or preset lumen level. The lumen con system (315) coupled to a lamp driver (310) initially reduces the power to the lamp (330) to prevent the lamp from being operated at power levels that result excess mean or preset lumen levels. With increased lamp usage, the lumen control system gradually increases power to the lamp to compensate for lamp lumen depreciation due to light-reducing mechanisms. By compensating for lamp lumen depreciation the lamp is operated at a constant mean or preset lumen output throughout the life of the lamp.