Density and speed of sound at 298.15 K have been measured for the ternary mixture methyl tert-butyl ether (MTBE) + 1-butanol + decane and for the binary 1-butanol + decane. In addition, excess molar volumes and excess isentropic compressibilities were calculated from the speeds of sound, densities, cubic expansion coefficient, and literature heat capacities. Attending to the symmetry of experimental V-E and kappa(S)(E) binary data, suitable fitting equations have been used. For the ternary data, different polynomial equations have been tested in order to minimize the set of parameters needed to correlate adequately. Experimental data were also used to test several empirical expressions for estimating ternary properties from experimental binary results.