Experimental data of excess heat capacities for 29 binary liquid mixtures of various types have been correlated by the NRTL and UNIQUAC models. For nine of these mixtures data at several isotherms is included. The parameters of the models, six for the NRTL and four for the UNIQuAc, have been estimated by a minimization technique using Simplex and Fletcher techniques simultaneously. The partial molar excess heat capacities at infinite dilution are also calculated. Agreement between experimental and calculated values is satisfactory except for associating and highly non-ideal mixtures. The UNIQUAC model performs better than the NRTL model.