Method for supervising a centrifugal separator with a separating chamber, a radially inner outlet connected to the separating chamber and to an outlet conduit, with a flow detector disposed in the outlet conduit and adapted to detecting a flow in the outlet conduit, and an intermittently openable radially outer outlet connected to the separating chamber. In order reliably and easily to supervise the intermittent discharge of the centrifugal separator, the pressure is measured by a sensor disposed in a portion of the centrifugal separator which is pressure-transmittingly connected to a central portion of the interior of the rotor. If the supervision unit does not detect a pressure drop pulse from the sensor within a predetermined period of time from when an intermittent discharge is initiated, an alarm signal is emitted.