Abstract: A cartridge-type oil-filtering assembly comprises two coaxially nested tubular filter elements of star-shaped cross-section consisting of undulating sheet material of fine and super-fine porosity, respectively, each filter element defining an annular array of generally triangular compartments. Respective compartments of the fine and the super-fine filter element communicate with each other through the pores of the super-fine filter element as well as through individual bypasses of relatively reduced cross-section; these bypasses may be formed by channels extending within annular face plates of the cartridge or by apertures in the undulation peaks of the super-fine filter element.