AGGREGATION PROCESSES IN HYBRID NANOSYSTEM POLYMER/NANOSILVER/CISPLATINHybrid nanosystems consisting of star-like copolymer Dextran-graft-Polyacrylamide in the anionic form (D-g-PAA(PE)), silver nanoparticles (AgNPs), and cisplatin (cis-Pt) have been synthesized in water and characterized by TEM, DLS, FTIR, and UV-Vis spectroscopies. It is shown that cis-Pt forms a complex with carboxylate groups of the polymer. For the ternary system Polymer/AgNPs/cis-Pt, a change in the hydrophilic-hydrophobic balance of a polymer molecule (due to the complexation with cis-Pt) and the aggregation of macromolecules, as well as to some agglomeration AgNPs, are revealed. The decrease of the antitumor efficiency of the hybrid ternary nanosystem Polymer/AgNPs/cis-Pt in comparison with the Polymer/cis-Pt system is discussed.K e y w o r d s: silver nanoparticles, branched polymer, polyelectrolyte, cisplatin, aggregation.