Densities for binary mixtures of diethylamine and s-butylamine with acetonitrile have been measured at 288.15, 293.15, 298.15 and 303.15 K using a vibrating-tube densimeter. Excess molar volumes (V-m(E)) were determined. Both systems exhibit negative V-m(E) values over the entire composition range in the temperature range studied. ERAS-Model calculations allowing for self-association for the amines and complex formation between acetonitrile and amines were performed. The agreement between theoretical and experimental results is satisfactory only for mole fractions of amines less than 0.50. A simplified version of the model, without the chemical contribution, gives similar results.