Abstract: A power transistor is disclosed. In one embodiment, the power transistor has a cell array including a semiconductor body having a plurality of transistor cells with gate electrodes and with body and source electrode regions and at least one temperature sensing device integrated in the semiconductor body. The temperature sensing device is formed in a selected sense zone within the cell array, and the transistor cells lying in at least one zone of the cell array that is directly adjacent to the sense zone have an increased W/L ratio of their channel width (W) to their channel length (L) compared with the other transistor cells of the cell array.