Abstract: An offset printing machine with variable format comprises two upper transverse rails extending between two front and rear longitudianl uprights of the frame of the machine. A cassette carrying the plate and blanket cylinders is suspended from these rails, during a movement of introduction or removal of said cassette, via upper rollers of horizontal and longitudinal axes mounted in the upper part of the cassette. These two upper transverse rails project forwardly with respect to the front upright of the frame. This front upright bears, on its outer face, two lower horizontal arms extending forwardly and on which the cassette rolls, during a movement of introduction or removal, via lower rollers of horizontal and longitudinal axes, mounted in the lower part of the cassette.