The density and the velocity of sound of liquid Li-Pb alloys have been measured in the composition ranges 0 - 17, 30 - 100 at % Pb and 0-10, 40 - 100 at % Pb, respectively. The temperature dependence of these properties has been determined for each sample in a temperature range of at least 130 K. The excess volume is negative and has a minimum at about 20at%Pb, where the volume per atom at 800 °C is about 19% smaller than the volume of an ideal solution. The absolute value of the excess volume rises with the temperature, as does the absolute value of the deviation of the adiabatic compressibility from the mean compressibility.