Quantitative description of the correlations between some characteristics (density, viscosity, asphaltene and sulfur contents, stability) of the vacuum residues and products of their visbreaking, and of the changes in the feed properties as a result of visbreaking in a real commercial visbreaker was done. The asphaltenes contents is higher in the petroleum products having higher density and viscosity. The higher the feed viscosity, the higher the visbreakate viscosity, but also the higher the relative decrease in the viscosity. There is no correlation between stability and the asphaltenes contents both for the feed and for the visbreakate. The higher the asphaltenes contents in the feed, the lower the relative increase in the asphaltenes contents during visbreaking. It indicates prevailing reactions of condensation of the asphaltenes precursors (resins, etc.) for the light stocks. For heavier stocks, cracking of the asphaltenes plays more significant role; starting from the asphaltene content in the feed of 7-9%, reactions of the condensation and cracking are approximately of the same rate, and increase in asphaltene content takes place mainly due to concentrating them in the visbreaking residue as a result of distillation of the visbroken product. Two groups of feedstocks may be defined from the point of view of their behavior in visbreaking: low-sulfurized (S<1%) and high-sulfurized ones (S>2%). In the feedstocks with low sulfur contents, the asphaltenes contents increases sharply, whereas for the high-sulfurized stocks the relative increase in the asphaltenes contents is low.