The use of alternate fuels in compression ignition (CI) engines is increasing day by day in the form of blends with diesel. Biodiesel is a non__ampersandsignndash;toxic, biodegradable and renewable alternative fuel that can be used with little or no engine modifications. The objective of this study was to investigate the effect of the biodiesel produced from soybean oil on single cylinder high speed diesel engine. Both performance and emission characteristics were studied in the range of no load to full load. The experimental results have showed that the brake thermal efficiency and mechanical efficiency of soybean biodiesel are better than diesel. Smoke is reduced by 19 % at part loads and NOx emissions are marginally increases at all loads with biodiesel operation.