The study of self-assembly processes in polymer solutions is the basis of a modern strategy for creating targeting systems for various substrates. In turn, the use of binary polymer/surfactant systems makes it possible to expand the range of polymers for creating drug delivery systems. This article describes the processes of formation of hybrid micelles based on carboxylterminal hyperbranched polyester polyol Boltorn H20[BH20-COOH] and surfactant Triton X-100[BH20-COOH/TX-100]. Using pH-metry, conductometry, dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), and scanning electron microscopy (SEM), it was shown that at pH = 6.5, a monodisperse [BH20-COOH] associate with a hydrodynamic diameter D h = 79 ± 10 nm and hybrid micelles [BH20-COOH/TX-100] with D h = 114.3 ± 6 nm are formed. Both types of supramolecular associates are able to effectively encapsulate the anticancer drug doxorubicin. The viability analysis of HeLa and MCF-7 cells was performed in the presence of doxorubicin-loaded [BH20-COOH] and hybrid micelles [BH20-COOH/TX-100] in vitro.