Olive pomace oil is a non edible by-product stream from olive oil production process with low acquisition cost, appropriate for supporting biodiesel production in the Mediterranean countries. The main goal of this paper is to present experimental procedures carried out to optimize experimentally the pretreatment process for this feedstock in order to convert free fatty acids (FFA) to their respective methyl esters. Thus, an acid esterification process with sulfuric acid as catalyst was employed and evaluated for different acid-to-oil and methanol-to-oil ratios over the process time. The initial results are showing that olive kernel oil can be efficiently processed in order to decrease the free fatty acid concentration and improve the biodiesel potential of this feedstock. (C) 2011 Elsevier Ltd. All rights reserved.