This study consists of the optimization of the methyl ester yields produced via transesterification of palm oil using CaO/Al2O3 solid base catalyst. Response Surface Methodology (RSM) in combination with Central Composite Design (CCD) was used to optimize the operating parameters. Alcohol/oil molar ratio, catalyst content in the reaction medium and reaction temperature were chosen as the variables and the response selected was the amount of methyl ester yields. All the reactions were performed in a batch laboratory scale reactor for 5 h: the optimum reaction conditions obtained were approximately alcohol/oil molar ratio of 12:1, catalyst content of 6 wt.% and reaction temperature of 65 degrees C. The results from ICP-MS exhibited insignificant leaching of the CaO active species into the reaction medium and the reusability of the catalyst was successfully tested in two subsequent cycles. Under certain reaction conditions the glycerol obtained was almost colorless. (C) 2009 Elsevier B.V. All rights reserved