A power tool, especially power saw, having a two-stroke internal combustion engine, that is provided with a substantially horizontally arranged cylinder, a cooling air blower, with guide surfaces directed towards the belonging therewith and arranged on one side of the cylinder, and a muffler connected to the cylinder outlet. The muffler has an exhaust gas inlet conduit which is in communication with an expansion chamber of the muffler. At least part of the walls of the muffler which are subjected to exhaust gas emanating from the cylinder chamber belonging therewith are arranged, when viewed in the direction of flow of cooling air, before the cylinder of the motor and are adapted to present guide surfaces for a stream of cooling air.