In the Present Investigation Experimental Work Has Been Carried Out to Analyze the Emission and Performance Characteristics of a Single Cylinder 3.67 Kw, Compression Ignition Engine Fuelled With Mineral Diesel and Diesel-Biodiesel Blends at an Infection Pressure of 200 Bar. the Performance Parameters Evaluated Were Break Thermal Efficiency, Break Specific Energy Consumption (Bsec) and the Emissions Measured Were Carbon Monoxide (Co), Carbon Dioxide (Co2), Hydrocarbon (Hc), and Oxides of Nitrogen (Nox). the Results of Experimental Investigation With Biodiesel Blends Were Compared With That of Baseline Diesel the Results Indicate That the Co Emissions Were Slightly Higher, Hc Emissions Decreased from 12.8 % For B20 and 2.85 % For B40, Nox Emissions Decreased Up to 39 % For B20 and 28 % For B40. the Efficiency Decreased Slightly For Blends In Comparison With Diesel the Bsec Was Slightly More For B20 and B40. from the Investigation It Can Be Concluded That Biodiesel Can Be Used As an Alternative to Diesel In a Compression Ignition Engine Without any Engine Modifications. Keywords: Diesel Engine, Karanja Biodiesel, Engine Performance, Exhaust Emissions, Cost Comparison.