A lighting unit with discharge lamps, particularly for spotlights and the like, including a discharge lamp inside a containment enclosure and ventilation elements for cooling the lamp, a control unit that drives a lamp power supply to supply variable power levels to the lamp and a fan power supply for actuating the ventilation elements at a variable speed. The control unit is controlled by signals imparted from outside and/or by signals that can be derived from measurements taken inside the lighting unit.