Automatic analyzers are compared (the traditional types AFSA, AD 86-5G, and minidistillation) to give the fractional composition of liquid oil products. There is an indisputable advantage in minidistillation analyzers of generations 1, 2, and 3. A basic aspect of successful realization for minidistillation analyzers is considered: the algorithm for transferring from the factual measurements in the liquid phase of the oil product to the data obtained in accordance with GOST 2177-99. It is found that the new algorithm provides results that satisfy the requirements of that standard for all pale oil products. The algorithm has been checked out on a considerable body of experimental data.The PMD-100 (110) instruments (Polotsk minidistillation) are increasingly used in the automatic analysis of oil product fractional composition [1,2]. Out of the analyzers for minidistillation of the first, second, and third generation, those of the second generation produced by the Polotsk State University together with the firm of ISL (France) were realized throughout the world in 2002, and in 2008 they were included in the international standard ASTM under the notation AD 7345. Table 1 gives the characteristics of some traditional automatic fractional composition analyzers and some minidistillation ones.Practical use of minidistillation data as recorded on the liquid phase of a boiling oil product requires transfer to GOST 2177-99 (ASTM D 86), which users employ. When one processes the characteristics of various liquid oil products, allowance must be made for their properties; one also has to consider methods of monitoring the temperature and the proportion of distillate, and also methods of determining the start and end of boiling for a boiling oil product, and the differences in apparatus.In standard methods (GOST 2177-99 or ASTM D 86), the start of boiling is determined from the fall of the first drop in the receiving cylinder, while the end of boiling is determined from the maximum attainable temperature of the oil product during distillation. To monitor the distillation temperature by standard methods, one uses a glass thermometer of type TIN 4.1 (TIN 4.2) or ASTM 7C (ASTM 8C), which is installed in accordance with the rules at the outlet of the vapor in the upper