The speed of sound u and density ρ for the binary mixture hexane + hexadecane has been measured as a function of composition and temperature along the saturation line between 293.15 K and 373.15 K. The speed of sound was measured by a pulse-phase echo ultrasonic device at a frequency of (1 to 5) MHz with an uncertainty of ± 0.1%. The density was measured by an Ostwald-Sprengel-type pycnometer with an uncertainty of ± 3 x 10(-5) g• cm(-3). The experimental results were used to calculate deviations of the speed of sound &UDelta; u, excess molar volume V-E, and isentropic compressibility k(S). The values &UDelta; u and V-E were fitted by the Redlich-Kister equation.