The vapor pressures of (propyl ethanoate + heptane), (propyl ethanoate + cyclohexane), and (propyl ethanoate + 1-hexene) and of all the pure components were measured by means of a static device at temperatures between (263 and 363) K. The data were correlated with the Antoine equation. From these data, excess Gibbs functions were calculated for several constant temperatures and fitted to a fourth-order Redlich-Kister equation. All the systems show positive deviations from ideality. Additionally, molar excess enthalpies for the three binary systems of propyl ethanoate with heptane, cyclohexane, and 1-hexene at a temperaure of 298.15 K have been carried out using a C80 II (Setaram) calorimeter. The excess properties were compared with the results using the available "ester" main group of the group contribution method Modified UNIFAC (Dortmund), which is a well-known model for the prediction of phase equilibria and excess properties.