Molecular properties of hyperbranched macromolecules-nanoparticles obtained by copolymerization of methyl methacrylate with the branching agents m-ethyleneglycol dimethacrylates at m = 1 and m = 3, have been studied by the methods of hydrodynamics and dielectric spectroscopy. By means of comparison with the linear poly(methyl methacrylates) it is shown that the conformational properties of these macromolecules can be characterized as the intermediate between statistical Gaussian coils of linear polymers and dendrimers. Their hydrodynamic behavior in solution does not correspond to solid unpenetrative nanoparticles. The influence of the length of branching agent on kinetic properties of hyperbranched copolymers of methyl methacrylate with m-ethyleneglycol dimethacrylates has been established. Refs 28. Figs 8. Tables 1.