The subject matter of the present invention is a pump arrangement (1, 10, 20, 30, 40, 50), in particular for use in the body's own vessels, having a pump (11, 41, 51) and a sheath (12, 42, 52) receiving the pump, bounding a flow passage (S) and having a distal intake opening (13, 43, 53) and proximal outflow opening (14, 29, 39, 44, 54) for producing a driving flow by means of the pump, wherein the pump is arranged in a first fluid-tight section (12a, 42a, 52a) having the distal intake opening and a second fluid-tight section (12b, 42b, 52b) includes the proximal outflow opening. In accordance with the invention, a further inlet opening (15) is present between the first section and the second section and is arranged between the intake opening and the outflow opening, with the first section and the second section being arranged with respect to one another such that the inlet opening opens into the flow proximal to the pump.