Ternary excess molar enthalpies, H-m(E), at 298.15 K and atmospheric pressure measured by using a flow microcalorimeter are reported for the (methanol + ethanol + tetrahydropyran) and (methanol + ethanol + 1, 4-dioxane) mixtures. The pseudobinary excess molar enthalpies for all the systems are found to be positive over the entire range of compositions. The experimental results are correlated with a polynomial equation to estimate the coefficients and standard errors. The results have been compared with those calculated from a UNIQUAC associated solution model in terms of the self-association of alcohols as well as solvation between unlike alcohols and alcohols with tetrahydropyran or 1,4-dioxane. The association constants, solvation constants and optimally fitted binary parameters obtained solely from the pertinent binary correlation predict the ternary excess molar enthalpies with an excellent accuracy. (C) 2003 Elsevier Science B.V. All rights reserved.