Excess enthalpies, H(E), at 298.15 K and atmospheric pressure are reported for binary liquid mixtures of alkanenitriles + n-alkanones. These experimental results, along with literature data on liquid-vapor equilibria (excess Gibbs energies), G(E), excess enthalpies, H(E), and activity coefficients at infinite dilution, gamma(i)infinity, are interpreted in terms of the DISQUAC group contribution model. The systems are characterized by three types of contact surfaces : nitrile (CN), carbonyl (CO) and alkane. The interchange energies of the alkane/CN and alkane/CO contacts were determined independently from the study of n-alkane + nitrile and n-alkane + ketone systems. The interaction parameters of the CN/CO contacts are reported in this work. The quasi-chemical parameters for alkanenitrile + ketone are zero except for ethanenitrile-containing mixtures. The dispersive parameters depend on the environment of the CN and CO groups. In general, the model provides a fairly consistent description of the excess functions G(E) and H(E) as functions of composition of the n-alkanenitrile + n-alkanone mixtures investigated.