The aim of this study is the evaluation of niobium catalysts (niobic acid, niobium phosphate) in the esterification reactions of fatty acids (C12-C18) with alcohols (methanol, ethanol, butanol). The catalysts were characterized by different techniques (N-2 adsorption/desorption, XRD, FTIR, FTIR of adsorbed pyridine). The niobium phosphate was the most active in esterification of lauric acid with butanol and can be reutilized three times without loss of activity. (C) 2012 Elsevier B.V. All rights reserved.