The drawbacks associated with conventional processes for the preparation of biodiesel can be overcome by using lipases as alternate catalysts. Lipases exhibit the ability to esterify and transesterify both fatty acids and acyl glycerols. Different approaches reported in the literature for the preparation of biodiesel from various feedstocks are described in the chapter. The major problem for lipase-catalyzed preparation of biodiesel is deactivation of the lipase in the presence of short chain alcohols like methanol and ethanol. Methodologies reported for stabilizing the lipases and the use of alternate acyl donors are also reviewed.