Transesterification reaction of Jatropha curcas oil with methanol was carried out in the presence of ash generated from Palm empty fruit bunch (EFB) in a heterogeneous catalyzed process. The ash was doped with KOH by impregnation to achieve a potassium level of 20 wt.%. Under optimum conditions for the EFB-catalyzed (65 degrees C, oil/methanol ratio of 15, 90 min, 20 wt.% EFB ash catalyst) and the KOH-EFB-catalyzed reactions (65 degrees C, oil/methanol ratio of 15,45 min, 15 wt.% of KOH doped EFB ash), biodiesel (>98%) with specifications higher than those stipulated by European biodiesel quality standard EN 14214 was obtained. (C) 2011 Elsevier Ltd. All rights reserved.