Unrefined rice bran oil (UNRFRBO) with high free fatty acids (FFA) is used as a source for the production of unrefined rice bran oil methyl ester (UNRFRBOME). Three-stage transesterification process is successfully used. Initially, the FFA of UNRFRBO is reduced to 1% (0.8%) by using two stages esterification process with methanol in the presence of acid (H₂SO₄) as a catalyst. Finally, biodiesel has produced by alkaline (NaOH) catalyzed transesterification process which has designed according to the central composite design. 90% has obtained at the optimum values of CH₃OH (20% v/v of oil), NaOH (1.0% w/v of oil), reaction time (60 minutes) and reaction temperature (55^°C to 60^°C).