Certain generalizations and calculation techniques were examined for determining the distribution of fractions and chemical compositions of crude oils within the limits of the standard boiling points. Distribution parameters were calculated on the basis of volume. The solution for normalizing the distribution in mole fractions was discussed and a fractional analysis scheme was developed to eliminate the difficulties in evaluating new crudes by determining the average molecular weights of the distillates and the residues. Crudes from the Kuibyshev, Middle Ob, and Orenburg oblasts, the Umm Shaif and Murban fields of the Near East, and other areas were assessed.