In industrial plants, centrifugal pumps are frequently operated in parallel config-uration, not least for redundancy and operational reliability reasons. However,regarding the resulting pressure pulsations and energy consumption, this opera-tion mode has so far not been in the focus of scientific studies. The object of thepresent article is to clarify the effect of parallel operation with respect to the obser-vable pressure pulsations. Measurements were carried out with two identical cen-trifugal pumps operating in parallel mode in an industrial-scale closed-loop pip-ing system. The results suggest that, regarding both the resulting pressure pulsa-tions and the operating point of each pump, this operation mode is quite sensitiveto smallest rotational speed deviations as they may occur due to different motorslip. The results indicate furthermore that, for minimum pressure pulsations,equal power consumptions of the two pumps are crucial, but not necessarily equalrotational speeds.