Scarcity of diesel is an ever growing problem since fossil fuel resources are limited. In this book an effort has been made to tackle this problem by giving biodiesel an option to solve the problem. In the present work, non-edible seeds of nahar, castor, and rice bran have been chosen for study since they are available abundantly in the north eastern part of India. Oil is extracted from these seeds and methyl esters are prepared. Two blends, B10 and B20 are prepared from each of the methyl esters prepared from nahar, castor, and rice bran. Fuel characterization has been done to determine various properties of the fuel like flash point, fire point, cloud point, pour point, calorific value, density etc. The performance characteristics have been studied and analyzed to determine the various output parameters of the engine like brake thermal efficiency, specific fuel consumption, indicated power, etc. The results can be further used to conduct an exergy analysis and optimization of the parameters for the combustion process which will help us to use biodiesel as an alternative fuel in today's energy needs.