The atomic and structural contributions proposed by Schroeder (Partington, 1949) for estimating the molar volume at the normal boiling point have been revised to improve the accuracy. Extensive testing with data for 163 organic liquids gave average and maximum absolute deviations of 1.4% and 7.2%, respectively. The corresponding average absolute deviations for the Schroeder (Partington, 1949), LeBas (1915) the Tyn and Calus (1975) methods are found to be 3.6%, 2.9% and 2.5%, respectively.