Biodiesel is a form of renewable energy that provides a less polluting fuel for diesel engines with minimal reduced engine performance as a result of a slight power loss and specific fuel consumption increase. To extend the use of biodiesel, the main concern is the economic viability of producing biodiesel. This study identified that the price of the feedstock was one of the most significant factors. Also, glycerol was found to be a valuable by-product that could reduce the final manufacturing costs of the process up to 6.5%, depending on the raw feedstock used. Biodiesel can only compete with diesel fuel prices. (c) 2005 Elsevier Ltd. All rights reserved.