The effects of C60 and C70 fullerenes added to a reaction mixture during the initiation of block polymerization of methyl methacrylate on the hydrodynamic and electrooptical properties of the synthesized fullerene-containing derivatives of PMMA, namely, PMMA-C60 and PMMA-C70, was examined. Based on the diffusion and viscometry data in chloroform, benzene, and ethyl acetate, the molecular mass and the size of the polymer macromolecules were estimated. The heterogeneity of polymer samples was assessed. It was shown that, in terms of their electrooptical and hydrodynamic properties, fullerene-containing derivatives of PMMA markedly differ both from each other and PMMA prepared using the same method but in the absence of fullerene.