Abstract: An air filter system for an internal combustion engine comprises a caisson which contains a series of superposed compartments containing horizontal, removable filter elements, each of which elements is supported on a wedge-shaped slide which, in turn, is supported on an inclined wall which allows the slide and filter element to be removed from the inlet side of the caisson for replacement of the filter elements. The inclined walls are alternated with horizontal walls, the latter being provided with openings into which the filter elements are inserted, and the entire series of superposed compartments can be formed from a single sheet of metal bent into a zig-zag configuration.