The present invention relates to an eccentric arrangement for a reciprocating piston pump, having a drive shaft drivable by a drive device, an eccentric part of a rubber-elastically deformable material is disposed on the drive shaft in a manner fixed against relative rotation. A bearing ring is provided on an outer circumferential surface of the eccentric part, by which ring a reciprocating piston is displaceable driven substantially perpendicular to the drive shaft. To avoid stroke losses, first and second support faces are provided on the drive shaft which the eccentric part disposed between them in such a way that the eccentric part rests with its axial ends on the first and second support faces.