Excess molar enthalpies, H-m(E) were determined as a function of molar fraction at 308.15 K and at atmospheric pressure for the binary mixtures containing propylene carbonate with ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, poly(ethylene glycol)-200, poly(ethylene glycol)-300, poly(ethylene glycol)-400, and poly(ethylene glycol)-600. Values of H-m(E). range from a maximum of about 1640 J mol(-1) (propylene glycol) to a minimum of about -386 J mol(-1) (PEG-600). All mixtures containing monodisperse glycols have positive values of H-m(E). Also PEG-200 presents a curve of H-m(E) versus x(1) (the molar fraction of glycol, component 1) always positive, whereas PEG-600 presents negative values of the heat of mixing over the whole range of the molar fraction. Finally, PEG-300 and PEG-400 show an inversion of sign of H-m(E), at about x(1) = 0.7 and 0.3, respectively. The experimental data were correlated using the Redlich-Kister polynomial and the adjustable parameters were obtained by the least-squares method. A qualitative discussion have been made in terms of intermolecular H-bonds. (C) 2003 Elsevier B.V. All rights reserved.