The synthesis of DNA, RNA and protein was measured in the lymphoid cells of the palatine tonsils in children aged from 3 to 15 years. The rate of RNA synthesis was also studied in the peripheral blood lymphocytes of men and women of different age and also in the patients with Shereskevsky-Turner's syndrome. 3H-thymidine incorporation into the tonsillar lymphocytes was independent of sex. 3H-uridine incorporation both into the palatine lymphocytes and into the peripheral blood lymphocytes in persons under 20 years of age and over 50 years old was greater in males. The rate of RNA and protein synthesis in the lymphocytes with kariotype 45,XO proved to be greater than in the lymphocytes with kariotype 46,XX and 46XY. The detected differences are discussed from the aspect of sex differences of the hormonal background and dyshormonal condition in patients with Shereshevsky-Turner's syndrome and possible differences in the temporary parameters of the mitotic cycle.