The invention relates to a piston pump for a slip regulating device in a hydraulic automobile brake system. For a more economical production, the invention provides a piston (40) of the piston pump to be constructed as a composite piece with a core (42). The core (42), for example, can be made of steel and surrounded by a plastic sliding case (44). The sliding case (44), for instance, can be placed on the core (42) by means of extrusion-coating and can also be pressed or pushed onto the core (42). The sliding case removes the need for costly subsequent machining of the piston surface, for example through grinding, and improves the sliding properties of the piston (40).