In this work, a group-contribution equation of state that takes into account association effects (GCA-EoS) is extended to model the phase behavior of fatty esters (biodiesel) in binary mixtures with glycerol, alcohols and water and ternary mixtures with glycerol and methanol. A new associating group (glycerol hydroxyl group: OHGly) was defined to take into consideration the association effects in the glycerol molecule. Self-association of methanol, water and glycerol and cross-association between methanol-glycerol, alcohol-ester, water-ester and glycerol-ester groups were considered. New pure-group, binary interaction and association parameters have been determined. The correlations and predictions of the model are found in acceptable agreement with selected experimental data reported in the literature. (C) 2010 Elsevier B.V. All rights reserved.