The presence of relatively high levels of naphthenic acids in crude oil may cause serious corrosion problem at temperature between 200 degrees C and 400 degrees C. One of the viable processes for decreasing acidity is the esterification of the present acids using an alcohol such as methanol. Therefore, the aim of this work is to develop a solid catalyst for the esterification reaction of 3-cyclopentylpropionic acid representative of the naphthenic acids. The esterification reaction is carried out at 80 degrees C, 3.5 kg/cm(2) of pressure in a mechanically stirred batch reactor, using Mg-Al hydrotalcite (Mg/Al = 4) with different activation treatments as catalyst. These solids are characterized by N-2 sorptometry and X ray diffraction. The higher concentration of Bronsted basic sites present in uncalcined hydrotalcite would explain the satisfactory performance obtained. TAN decreased 90% by operating at a temperature as low as 80 degrees C after 60 min of reaction. The catalytic activity is evaluated at different reaction conditions such as, mass of catalyst, stirring speed and reaction temperature. A kinetic study for heterogeneous esterification of 3-cyclopentylpropionic acid with methanol was performed.