The objective of this work was to study the two-step acid base homogenous catalyzed transesterification of olive pomace oil, with the ultimate purpose of producing biodiesel under mild reaction conditions by optimizing the process. Optimization of the experimental procedure was conducted by a factorial design of 23 under the acidic pretreatment step and during the basic transesterification. The optimal production of methyl esters (97.8%) was achieved for the experimental conditions H2SO4=20 wt%/CH3OH=35:1/T=40 degrees C and KOH=0.6+ fatty acid value /CH3OH=9:1/ T=60 degrees C, in the acidic and basic stage of the process, respectively. Finally, to properly assess the quality of the biofuel produced, it was tested for all the European Standard properties.