The densities and speeds of sound of (toluene + isooctane), (MTBE + toluene), and (MTBE + isooctane) were measured at four temperatures from (298.15 to 328.15) K, and the respective values of excess volumes V-m(E) and adiabatic compressibility K-S were calculated. The V-m(E) and K-S values were fitted to the fourth-order Redlich-Kister equation. The V-m(E) values for (MTBE + toluene) are negative and decreasing with increasing temperature. The other systems show positive V-m(E) with comparatively small temperature dependence. (C) 2009 Elsevier Ltd. All rights reserved.