Empty Fruit Bunch (EFB) resulted from oil palm plantations and mills can be converted into ash through open combustion. The EFB ash then treated by simple calcination and used as a heterogeneous catalyst for biodiesel production. The characteristics of EFB ash were identified based on its elemental composition, porous structure, and active site size. The effectivity of the EFB ash as a catalyst was tested in a transesterification reaction of Refined Bleached Deodorized Palm Oil (RBDPO) with excess methanol (30%-w) in various catalyst loads (in %-wt). The lab-scale experiments were conducted in a three-neck glass reactor, which was put on the hot plate stirrer at 450 rpm. The EFB ash performed the best as a catalyst by attaining optimal conversion at 65°C for 1 hour with a 16%-wt of catalyst load. In this condition, most of the standard quality of biodiesel were complied with total glycerol under 0.24 % and ester methyl contents up to 98.9%. The characteristics tests showed that the properties and active side of the EFB ash are excellent after calcination at 600 for 5 hours. The recyclability test of EFB ash as a catalyst showed high performance in two repetition cycles, each showing an increase in the yield of biodiesel, which was 92.21% in cycle 2 and 91.23% in cycle 3.