The influence of different groups of diesel hydrocarbons on the physicochemical properties and performance characteristics of diesel fuels has been considered. The parameters to be evaluated have been cetane number, cetane index, diesel index, pour point, and cold filter plugging point. It has been shown that the hydrocarbon group composition, which reflects only the amount of arenes and paraffinic-naphthenic hydrocarbons, gives insufficient information for prediction of the performance properties of fuels. A more detailed study of the hydrocarbon composition of each group of compounds-the ratio of mono-, bi-, polycyclic arenes, the concentration and the ratio of high- and low-melting-point n-alkanes and isoalkanes-has made it possible to reveal the influence of each group on individual fuel characteristics.