The hydrodynamics induced by a Moritz HAS impeller are investigated using the PIV technique. The purpose of this study is to extend the knowledge of this kind of impeller, well known in turbulent flow, to the transition regime and laminar flow. Measurements of instantaneous velocity fields, are synchronized with the position of the blade of the impeller. The periodic motion induced by the impeller blade rotation is measured by this conditional averaging. A triple decomposition is used to analyze the levels of turbulent kinetic energy and. periodic kinetic energy induced by the impeller. In a turbulent regime; the impeller induces axial flow: the magnitude of periodic fluctuation is low compared to the turbulent one. In a laminar regime, the impeller induces a tangential-radial discharge flow, and periodic velocity, fluctuations are limited to the vicinity of the impeller.