The vapour pressures of liquid cyclohexane + N,N,N’,N’-tetramethylalkanediamine, (CH3)(2) N(CH2)(u)N(CH3)(2) (u = 1,2) + cyclohexane mixtures were measured by a static method between 303.15 and 343.15 K at 10 K intervals. The excess molar enthalpies at 303.15 K were also measured. The molar excess Gibbs energies, calculated from the vapour-liquid equilibrium data, and the molar excess enthalpies compare satisfactorily with group contribution (DISQUAC) predictions. The proximity effect of N atoms produces a regular decrease of the interactional parameters.