Depletion of fossil fuel leads the research to be focused on alternate source for biofuel production. Though various sources have been identified for the production of biofuel, their availability and cost of manufacturing was found to be high. Macroalgae are most promising feed stock to their wide spread availability and higher lipid content. Extraction of biofuel from algae was found to be the best method of biofuel production. The main aim of the project is to make use of the marine algae such as Gracilaria corticata collected from Covelong, Tamil Nadu and Ulva sp., from Kanyakumari, Tamil Nadu to extract the useful algal oil meant for biofuel production and study the GC-MS characteristics of biofuel extracted from it. Results showed that the presence of dodecamethyl (34.19% area) in Gracilaria corticata and 36.6% area decanoic acid in Ulva sp which confirmed the biodiesel.