The activity of a heterogeneous magnetic catalyst was studied in detail in the studies presented herein. The SrO/MnFe2O4 catalyst was synthesized in sequential steps; SrO was obtained by decomposing SrCO3 at 1100°C for 5 hours and then impregnated into a magnetic support (MnFe2O4) synthesized by the co-precipitation method using Iron (III) chloride and manganese chloride. The catalyst was efficiently used in transesterification reactions of babassu oil for the production of biodiesel with 72% yield when applied in a 5:1 SrO/MnFe2O4 molar ratio. The catalyst was optimized through several reaction parameters, and its best conditions were: catalyst percentage of 4% in relation to oil, alcohol / oil molar ratio of 9:1, reaction time of 4 hours and temperature of 65°C. For characterization of the material, VSM, TGA, DRX and FTIR techniques were used.