Petroleum or gasoline based mostly oil fuels worldwide haven't simply resulted within the quick or rapid consumption of conventional energy sources however have in addition caused serious air and atmosphere contamination. The search for a substitute fuel has prompted numerous discoveries as a result of that a wide variety of alternative fuels are available to us at our disposal currently. The current investigations have revealed the utilization of vegetable oils for CI engines as an alternative for diesel fuel. But there's a limitation in utilizing straight vegetable oils in diesel engines because of their high viscosity and low volatility. In the present work mahuwa seed oil is converted into mahuwa seed methyl ester (MSME) through transesterification process. In the first phase of work, tests are conducted by using different blends of mahuwa seed methyl ester with diesel in a single cylinder with four stroke vertical and water-cooled Kirloskar diesel engine. The experimental result of fuel blends (MSME10, MSME20, MSME30, MSME40, MSME50 and MSME100) are compared with diesel oil (D100). The brake thermal efficiency, mechanical efficiency, unburned hydrocarbons and CO, NOX are found to be lower just in case of MSME bio fuel blends than the diesel. And the results are indicated that the blend MSME20 have nearly the same emissions and performance characteristics as of the diesel fuel. Brake specific fuel consumption for blend MSME20 is 0.21kg/kW-h at full load condition be nearer towards diesel is 0.19kg/kW-h. The brake thermal efficiency for mahuwa mahuwa seed bio fuel blend MSME20 is 31.91% and it had been nearer towards the diesel fuel is 34.33% at full loading condition. The base test results demonstrated that the MSME20 blend having equivalent characteristics to those of diesel fuel. This prompted the conclusion that the blend MSME20 is the most suitable blend when compared with other MSME blends and therefore MSME20 is the substitute for the diesel and which is able to reduce the diesel utilization nearby 20%.