396Due to depleting conventional energy resources, environmental degrada- tion, and hike prices of oil in worldwide, there is a dire need to look for sustainable, greener fuels which are economical as well as environment friendly. At present scenario, microalgae appear to be the only biosolution that can replace conventional fossil fuels completely. This chapter briefly overview the use of microalgae as future feedstock for biodiesel produc- tion and critically described their downstream processes. The challenges and future aspects for commercialization of biodiesel production from micro- algae through genetic modification and metabolic engineering can also be used to enhance photosynthetic efficiency and higher microalgae oil yield.