Abstract: The production of biodiesel from vegetable oils stands as a new versatile method of energy generation in the present scenario. Biodiesel is obtained by the transesterification of long chain fatty acids in presence of catalysts. Transesterification is an attractive and widely accepted technique. The purpose of the transesterification process is to lower the viscosity of the oil. The most important variables affecting methyl ester yield during the trans esterification reaction are the molar ratio of alcohol to vegetable oil, reaction temperature, catalyst amount and time. Biodiesel is renewable, biodegradable, non-toxic, and essentially free of sulfur and aromatics.