Excess molar enthalpies at T = 298.15 K and atmospheric pressure of (ethyl propionate + n-hexane + I-pentanol), and of(n-hexane + 1-pentanol) and (ethyl propionate + 1-pentanol) are reported. A Calvet microcalorimeter was used as measuring device. Variable degree polynomials were fitted to the experimental set of data. The group contribution models of Chao et al., and UNIFAC (in the versions of Tassios, Larsen, and Gmehling) were used to estimate ternary excess enthalpy values. Several empirical expressions for estimating ternary properties from binary results were also tested.