This study provides a description of a pitched blade impeller as an axial pump. For the turbulent flow regime of an agitated liquid in a fully baffled cylindrical vessel under a few simplifying assumptions, we formulate the relation among the impeller dimensionless total head, the impeller power number, and the dimensionless impeller pumping capacity (the flow number). The hydraulic efficiency of pitched blade impeller is determined from experimental data found in literature (the flow numbers and the power numbers). It follows from the results of the calculations that the hydraulic efficiency of pitched blade impellers increases significantly with decreasing pitch angle, and also with decreasing impeller vessel diameter ratio. (C) 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.