Excess molar volumes at 298.15 and 308.15 K and excess molar enthalpies at 308.15 K and atmospheric pressure were measured for {x(1) di-n-butyl ether + x(2) 1-propanol + (1 - x(1) -x(2)) n-octane) and their corresponding binary mixtures, using a DMA 60/602 Anton Paar densimeter and a standard Calvet microcalorimeter. Experimental data were compared with the predictions of the UNIFAC I (version of Tassios), UNIFAC Il (version of Larsen), UNIFAC III (version of Gmehling) and Nitta-Chao group contribution models. Several empirical equations predicting ternary-mixture properties from the binary-mixtures data have been also examined.