A pollutant of concern to the mankind is the exhaust noise in the internal combustion engine. However this noise can be reduced sufficiently by means of a well designed muffler. The suitable design and development help to reduce the noise level, however, the performance of the engine should not be hampered by the back pressure caused by the muffler. In the current work, a reactive muffler was designed and fabricated and the transmission loss of the developed muffler was calculated at 1200 rpm. In addition, the current results were compared with the conventional muffler in term of brake thermal efficiency and brake specific fuel consumptions and drop of pressure is also measured.