Biodiesel is an alternative fuel derived from vegetable oils by modifying their molecular structure through transesterification process. Linseed oil methyl ester (LOME) was prepared using methanol in the presence of potassium hydroxide as catalyst. Use of linseed oil methyl ester in compression ignition engines was found to develop a very compatible engine-fuel system with lower emission characteristics. Two identical engines were subjected to long-term endurance tests, fuelled by optimum biodiesel blend (20% LOME) and diesel oil respectively. Various tribological studies on lubricating oil samples drawn at regular intervals for both engines were conducted in order to correlate the comparative performance of the two fuels and the effect of fuel chemistry on lubricating oil performance and life. A number of tests were conducted in order to evaluate comparative performance of the two fuels such as density measurement, viscosity measurements, flash point determination, moisture content determination, pentane and benzene insolubles, thin layer chromatography, differential scanning calorimetry etc. All these tests were used for indirect interpretation of comparative performance of these fuels. Biodiesel fuels performance is found to be superior to that of diesel oil and the lubricating oil life is found to have increased, while operating the engine on this fuel. NOTE: This paper was presented at the ASME 2003 Internal Combustion Engine Division Spring Technical Conference but was printed in the ASME 2003 Internal Combustion Engine and Rail Transportation Divisions Fall Technical Conference proceedings, pages 427–441. It should appear under the Lubrication and Friction heading.