Excess molar volumes of twelve binary alkanenitrile + 1-chloroalkane mixtures (ethanenitrile, propanenitrile or butanenitrile + 1-chlorobutane, + 1-chloropentane, + 1-chlorohexane or + 1-chlorooctane) have been measured using a vibrating-tube densimeter. Excess volumes for these mixtures are positive except for butanenitrile + 1-chlorobutane.