Abstract: Peripheral blood lymphocyte subsets in 40 normal subjects （23 males and 17 females） were studied using monoclonal antibodies. The mean values of B-cell, T-cell, Th-cell and Ts-cell numbers were 16.1±3.8%, 69.8±4.7%, 47.7±4.5% and 24.1±4.7%, respectively. The Th/Ts ratio was 2.1±0.5. There were no significantly difference between males and females in the values of lymphocyte subsets determined in our study.