Abstract: Pneumatically operated driving tool for fasteners comprising a working cylinder, a working piston within the working cylinder connected to a driver of the like, a stop in the working cylinder limiting the working stroke of the working piston, a control valve adapted to be actuated by a trigger, a working space above the working piston when the piston is in its upper dead point position, the control valve being adapted to alternatingly connecting the working space with a pressurized air source or with atmosphere, respectively, a piston return chamber surrounding the working cylinder and connected thereto by a first opening adjacent the stop, and a second opening spaced from the stop, the working piston having a smaller diameter than the working cylinder. An annular piston is sealingly displaceably located on the driver and sealingly engages the wall of the working cylinder.