A series of MgO catalysts have been prepared by calcination of (MgCO3)(4)center dot Mg(OH)(2) and these have been found to be effective for the transesterification of triglycerides with methanol at 200 degrees C. The calcination temperature controls the surface area, porosity and the surface structure and we observe that the optimal calcination temperature is in the range 550-700 degrees C as this provides a balance between high surface area, and hence high concentration of active sites, and the pore structure which permits access of the reactants. Using appropriate conditions conversions in excess of 98% could be obtained.