Biodiesel was synthesized by transesterification in the presence of NaOH as the catalyst. The project was developed with the goal of optimizing the biodiesel production starting from locally used frying oil. The process was implemented for a 400 L/batch production in rural areas, to be used on farms and to provide fuel for machinery and electricity generating. It was important to develop a robust and simple procedures and to use the minimum amounts of chemicals (e.g. NaOH). The reaction was performed employing an optimized methanol/oil molar ratio of 6:1 and a reaction temperature equal to 90 degrees C. A yield of 93.8% was achieved with low cost raw materials. The GC-MS, H-1 NMR, C-13 NMR, FT-IR and TGA/DTG analyses of the final product confirmed that in the chosen experimental conditions the biodiesel did not contain traces of glycerol. Its characteristics were found to be as good as those of the biodiesel obeying the European standards. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.