Excess molar volumes for ternary pseudo-binary mixtures of {(benzene + cyclohexane, or methylcyclohexane) + (acrylonitrile + cyclohexane, or methylcyclohexane)} have been obtained from the densities measured by means of an Anton Paar Model DMA 60/602 vibrating-tube densitometer at the temperature 298.15 K. Except for the mixtures with the mole fraction 0.7921 and 0.8287 cyclohexane, the V-m(E) values are negative over the entire composition range. For all mixtures, the V-m(E) values increase with the increase of the mole fractions of cyclohexane, or methylcylohexane. The results are discussed by comparing with those for the binary mixture without cyclohexane, or methylcyclohexane. (C) 1998 Academic Press.