The integral enthalpies of mixing △H for Cu-In, Cu-Sb, In-Sb and Cu-In-Sb liquid alloys were determined calorimetrically. The observed dependence of pH on the concentration of the binary and the ternary alloys could be described with the associate model. By the calculation of △H of the ternary alloys with the help of the associate model the parameters are fixed using the △H values of the base-binary liquid alloys.