In the present experimental research work, used vegetable oil methyl ester (UVOME) is produced through transesterification of used vegetable oil using methanol in the presence of two different catalyst such as sodium hydroxide (NaOH) and Potassium hydroxide (KOH). Experimental investigations have been carried out to examine the combustion and emission characteristics in a direct injection transportation diesel engine running with diesel, biodiesel (UVOME), and its blends with diesel such as B20N, B80N, B20K and B80K. A careful observations of the crank angle at which heat release occurs was carried out. The exhaust gas temperature and emission performance of diesel engine using diesel fuel and bio-diesel blends fuels such as B20N, B80N, B20K and B80K are compared. The result has shown that, biodiesel blends has higher exhaust temperature than diesel with significant reduction in emissions of CO, hydrocarbons (HC), but slightly increased in NOx emissions. © 2012 Pillay Engineering College. © 2013 Elsevier B.V., All rights reserved.