Studies were carried out on transesterification of Karanja oil with methanol for the production of biodiesel. The reaction parameters such as catalyst concentration, alcohol/oil molar ratio, temperature, and rate of mixing were optimized for production of Karanja oil methyl ester (KOME). The fatty acid methyl esters content in the reaction mixture were quantified by HPLC and H-1 NMR method. The yield of methyl esters from Karanja oil under the optimal condition was 97-98%. (c) 2005 Elsevier Ltd. All rights reserved.