The present study was initiated to determine the nature of flow in the suction pipe of centrifugal pumps. When a high specific-speed pump runs at partial discharges, it is known in general that some amount of liquid in the impeller flows back with a rotational component of velocity into the suction pipe and the liquid approaching the impeller is impelled to swirl before it reaches the impeller. Measurements of velocity and pressure distribution in this swirling flow were made at successive sections of the suction pipe and the distributions of energy were also evaluated. The results may help to make an analysis of three dimensional swirling flow in pipes.