A simple and reliable hydraulic or pneumatic cylinder is provided with an axially adjustable internal head which permits highly accurate selective variation of the stroke of the cylinder piston. A piston-cushioning device is carried by the adjustable head and can be regulated independently of the stroke adjustment to control the cushioning of the piston at the end of its stroke. In many applications employing pneumatic or hydraulic cylinders, it is necessary to adjust the length of the stroke of such a cylinder in accordance with different operating requirements. Another highly desirable feature of many conventional hydraulic or pneumatic cylinders, is the provision of a cushioning device which gradually retards the movement of the piston as it approaches the end of its stroke and which preferably is adjustable so that this cushioning effect can be regulated in accordance with different loads and operating pressures. In some cases, the effective stroke of a cylinder is reduced simply by means of an adjustable blocking member on the piston rod, but such an arrangement either sacrifices the aforementioned cushioning effect or requires the use of an elaborate valving system to achieve that feature. Furthermore, in pneumatic systems or other related systems employing a compressible working fluid, any arrangement for shortening the stroke of the piston without decreasing the volumetric capacity of the cylinder can be very inefficient. Accordingly, various adjustable stroke cylinders have previously been devised in which the stroke adjustment has been accomplished by axially moving a cylinder head or by changing the effective axial length of the piston itself. In general, however, the stroke adjusting means heretofore employed in such variable stroke cylinders have either entirely precluded the inclusion of adjustable piston cushioning means or have provided that feature only at the expense of very complicated and expensive mechanisms.