An oil separator for oil-flooded rotary vane vacuum pumps has a filter housing (10) and a plurality of filter cartridges (14) disposed therein through which the pumping medium flows. The filter cartridges (14) are each inserted through a respective opening (16) in an outer housing wall (12) of the filter housing (10) and are secured to the housing wall (12) so as to be detachable and tight with respect to media.