Flow measurements using a five-hole pressure prove were made in an unshrouded and a shrouded centrifugal impeller with 10 blades radial at the outlet. The measurements were made for a flow rate corresponding to nearly zero incidence angle and two other flows with reduced and increased flow rates. These measurements show that the low-energy region tends to move from the middle blade-to-blade position toward the suction side near the casing surface in the unshrouded impeller, and from the suction-side/shroud corner toward the hub side in the shrouded impeller. This tendency was observed upstream in passages of both impellers, as the flow rate was reduced.