The hydroconversion of vacuum residue (VR) with the recycle of the unconverted vacuum residue in the presence of nanosized MoS2 catalyst particles synthesized "in situ" in the hydrocarbon medium has been studied. Changes in the molecular structure of asphaltenes from VR and the products of VR hydroconversion in a mixture with the vacuum residue (recycle), depending on the residence time of asphaltenes in the reaction zone, have been described. The main features of structural transformations of asphaltenes during the hydroconversion with recycle have been established. Trends in the structural properties of the asphaltenes with varying different process parameters, such as the residence time and temperature in the reaction medium, have been compared.