Research into renewable sources of energy has been largely carried out because of the increasing energetic demand and the need of reducing the consumption of fossil fuels.1 Biodiesel is a largely studied biofuel obtained from lipids consisting mainly in fatty acid methyl ester (FAME). However, ethanol and other alcohols can be used. In the case of using vegetable oil the catalyst used is standardly alkaline such as NaOH to form the methoxide (reacting with methanol) which finally reacts with the oil forming the biodiesel-FAME. However, when the feedstock contains more than 1 % of free fatty acids (FFA), the saponification reaction can be a serious obstacle decreasing the yield to esters. In those cases, acid catalysts can be used for tests using feedstocks with high content of FFA. Fatty acid ethyl esters (FAEE) can be an alternative to FAME depending on the availability of the feedstock (ethanol and/or methanol). The aim of this work was the exploring of the esterification reaction using oleic acid and ethanol by using commercial alumina and solid waste residues as catalysts.