Excess molar volume, viscosity deviation, and molar refraction deviation for the chloroform +; acetonitrile system at 303.15 K were calculated from binary experimental results of density, viscosity, and refractive index over the whole mole fraction range, respectively. Isothermal vapor-liquid equilibrium data at the same temperature were also obtained and the excess molar Gibbs energy was calculated from these data. Each one of the properties was fitted to a Redlich-Kister type equation using least squares in order to obtain their dependencies on concentration. The presence of intermolecular association complexes was inferred from the viscosity deviations, leading to a 1:1 stoichiometric relationship. The recorded FTIR spectra confirm the existence of this type of hydrogen-bonded complex, making it possible, furthermore, to calculate the heteroassociation constant and enthalpy of formation of the hydrogen bond.