A process for detecting the operating state of a pump of a pump system, involves the steps of: detecting at least one pressure and/or flow profile P(t) in the pump system, computing of at least one characteristic value K.sub.kal from the pressure and/or flow profile P(t), comparing the computed characteristic value K.sub.kal with at least one defined characteristic value K.sub.vor or with a range bordered by the characteristic value K.sub.vor, the defined characteristic value K.sub.vor or the characteristic value range corresponding to the operating state of the pump of interest, and outputting the operating state determined by the comparison. With the process, the operating states of pumps, pump systems and hydraulic systems is determined by the computed characteristic value K.sub.kal characterizing the pulsation of the pressure and/or flow profile P(t) in a computation time interval .DELTA.t.sub.B, the pulsation quotient being computed as the computed characteristic value K.sub.kal.