The exposure of gold nanoparticles with different size on the morphological indicators of red bone marrow and peripheral blood of white not purebred rats at long peroral introduction were studied in experiment. The mutagen influence of gold nanoparticles on polychromatophilous erythrocytes of bone marrow were estimated by micronuclear test. During research the reduction of quantity of leukocytes in peripheral blood and the erythrocyte volume reduction with increase of their hemoglobin saturation were revealed.