The invention relates to a piston pump (10) for a hydraulic vehicle brake system having, in particular, slip-control. The invention provides that the piston (16) is configured as a hollow piston and is sealed by a piston sealing (28) which comprises a sealing lip, can be flown around in a direction toward the interior of the piston (compression chamber (26)), and which forms the one inlet valve of the piston pump (10). By virtue of the inventive piston pump, the provision of a separate inlet valve is no longer necessary while, at the same time, obtaining a piston pump (10) that comprises a short construction.