Ever-growing energy demands, diminishing conventional fossil fuel reserves and global inconsistent climatic changes due to emission of dangerous gases, has led to focus on environmental friendly, alternative renewable energy sources. Recently, biodiesels have emerged as the potential alternate to diesel fuel in renewable energy sources. The present work aims to evaluate the effect of fuel injection pressure on the emission characteristics of DI diesel engine when fuelled with Jatropha Curcas Oil Methyl Ester (JCOME). The experimental evaluation was carried out using a four-stroke, single cylinder, water cooled diesel engine fuelled with different blends (B20J, B40J, B60J and B100J) of JCOME at different fuel injection pressures varies from 210 to 240 bar. The test results revealed that B100 blend has lowest particulate matter (PM), CO emission, and higher NOx emission at all injection pressures and optimum emission values were observed at 220 bar for all tested biodiesel blends. The PM and CO emission was decreased with the increase of JCOME percentage in diesel blend. The PM, CO emission from diesel engine was low at 220 bar of injection pressure for all blend percentage of JCOME. The emission characteristics are optimal at fuel injection pressure of 220 bar and it can be treated as optimum injection pressure with reference to emisson parameters. Fuel injection pressure of 220 bar can be considered as rated injection pressure for the tested engine at full load condition in order to reduce the exhaust emissions .