In a centrifugal oil separator for blow-by gases of an internal combustion engine comprising a rotating component which has at least one inflow port for the introduction of blow-by gases from the crankcase of the internal combustion engine, at least a first outflow port for the discharge of air and at least a second outflow port for the discharge of oil, and also a driveshaft (12) driving the rotating component for driving the rotating component, the driveshaft of the rotating component is connected via a mechanical coupling to a transmission driven by a crankshaft of the internal combustion engine.