Three embodiments of a regenerative pump: the first embodiment is composed of a body and casing separated by an intermediate ring-like spacer having a central annular area the wall of which forms the outer peripheral boundary of a radially defined chamber through which move the vanes of an impeller rotatably mounted in the center of the spacer. Inlet and outlet ports are placed in fluid communication with each other by virtue of the chamber as the impeller rotates. Concentric and overlapping grooves formed on the upper surface of the body and the lower surface of the case have a particular geometry the arrangement of which leads to a substantial reduction in noise contributed by fluid flowing in the region of the outlet port. In a second embodiment of the invention, the downstream portion of each of the grooves extends along a gentle curved line which terminates substantially without deflection in the outlet hole. The third embodiment comprises a multi-stage pump in which the intermediate spacer is formed with an inclined surface adopted to form a smooth fluid connection with the vanes of the second or upper impeller. At the same time, at the position corresponding to the location of the communication hole of the second spacer, is formed with an inclined surface which is substantially parallel to inclined surface formed on the intermediate spacer.