Biodiesel derived from nonedible feed stocks such as Mahua, Jatropha, Pongamia are reported to be feasible choices for developing countries including India. This paper presents the results of investigation of performance and emissions characteristics of diesel engine using Mahua biodiesel. In this investigation, the blends of varying proportions of Mahua biodiesel and diesel were prepared, analyzed compared with the performance of diesel fuel, and studied using a single cylinder diesel engine. The brake thermal efficiency, brake-specific fuel consumption, exhaust gas temperatures, Co, Hc, No, and smoke emissions were analyzed. The tests showed decrease in the brake thermal efficiencies of the engine as the amount of Mahua biodiesel in the blend increased. The maximum percentage of reduction in BTE (14.3%) was observed for B-100 at full load. The exhaust gas temperature with the blends decreased as the proportion of Mahua increases in the blend. The smoke, Co, and No emissions of the engine were increased with the blends at all loads. However, Hc emissions of Mahua biodiesels were less than that of diesel.