A method and a system for detecting the speed of a pump motor of a hydraulic pump system are provided, in which pump system a pump is driven by a pump motor to deliver hydraulic fluid into a pump reservoir. In accordance with the present invention, a pressure signal representing the fluid-delivery activity of the pump is detected, and the pressure peaks within this pressure signal identified. The speed of the pump motor is determined on the basis of the frequency or the time intervals of these pressure peaks.