Continuous utilization of fossil fuels has been polluting our atmosphere with harmful exhaust emissions from the engines. Rapid increase in the cost of fossil fuels have also generated interest in search for the alternative fuels. One such alternative fuel for Compression Ignition (CI) engine applications is biodiesel. It is a renewable, biodegradable and clean burning fuel. In the present work, experiments have been carried out to study the performance and emission characteristics of a CI engine running on biodiesel. Injection timing was varied to obtain optimum performance and lowest emissions from CI engine. Comparisons were drawn with respect to standard diesel fuel performance and emissions. Results clearly indicated the optimum injection timing of 19° before top dead center (BTDC) for biodiesel. Also, the effects of injection timings on HC, CO and NOx emissions have been discussed.