In a plug valve with a plug (11) supported around its axis of rotation in a flow passageway of the valve housing (1), the plug is supported in a floating manner against a spring force pressing the plug against an annular sealing element (23). The spring force is provided by a spring element (20, 21) bearing against the valve housing (1) and engaging with a trunnion (16, 17) of the plug. The sealing element (23) is supported in a fixed position against a flow passage opening (2).