Technical Abstract: Defined as the long-chain fatty acid monoalkyl esters of vegetable oils, animal fats, or other lipids, biodiesel is an environmentally attractive alternative to conventional petroleum diesel fuel (petrodiesel). Produced by transesterification with a monohydric alcohol, usually methanol, biodiesel has several technical advantages over petrodiesel, such as inherent lubricity, low toxicity, derivation from a renewable and domestic feedstock, superior flash point and biodegradability, negligible sulfur content, positive energy balance, and lower exhaust emissions. Important disadvantages of biodiesel include high refined feedstock cost, higher oxides of nitrogen exhaust emissions, inferior storage and oxidative stability, lower volumetric energy content, and inferior low temperature properties. This chapter covers the preparation of biodiesel, the influence of fatty acid alkyl ester composition on fuel properties and alternative feedstocks for biodiesel production.