Exhaust noise of IC engine is known to be one of the most harmful pollutants to the mankind. However this noise could be reduced sufficiently by means of a well designed muffler. The appropriate design of muffler would able to reduce the noise, but at the same time the performance of the engine is being hampered by the back pressure of exhaust gases which needs to be removed from the engine to breathe it more efficiently. Similarly, from the operator's point of view, emanating sounds from the existing tractors are well above the safe acceptance limit. Thus, a study was taken up to look into effect of back pressure on engine performance and development of a new muffler for reduction in noise and provide comfortable and safer environment to the operator. Experiment has been carried out with existing muffler and two other selected mufflers of different tractors under varying throttle condition in laboratory. A mercury column Utube manometer was used to measure exhaust backpressure. Result reveals that backpressure value of existing muffler varying from 0.393 kpa to 4.316 kPa whereas 0.786 kPa -7.06 kPa with other mufflers. It suggested that interchangeability of mufflers to reduce noise level may adversely affect engine performance by increasing back pressure. The aim of this research is to evaluate the back pressure and afterward validate the theoretical results such as noise level, engine performances, and specific fuel consumptions of the existing and selected mufflers to provide a new design of muffler for better efficiency of man-machine system. The research is being under progress and the presented paper is a part of that research.