Viscosity and density have been measured for three binary mixtures of chlorinated methanes, that is, carbon tetrachloride + chloroform, carbon tetrachloride + dichloromethane, and chloroform + dichloromethane, and for one ternary mixture of 1:1 mole ratio (carbon tetrachloride + dichloromethane) + chloroform at 303.15 K. Molar excess volumes V-E and viscosity deviations were obtained for these mixtures. Molecular interactions have been interpreted from the results. There are very weak specific interactions between CCl4 and CH2Cl2 or between CCl4 and CHCl3. There are relatively stronger specific interactions between CHCl3 and CH2Cl2. The interactions between different chlorinated methanes decrease in the order CH2Cl2 --- CHCl3 > CCl4 --- CH2O2 > CCl4 --- CHCl3. The interactions are considered to be caused mainly by the differences in polarity, size, and shape between different component molecules.