Peripheral blood from 120 healthy subjects, of whom 59 were young (33.5 ± 9.6 years) and 61 aging (69.2 ± 4.2 years), was examined for the proportions and numbers of lymphocyte populations, with a battery of surface markers. Absolute lymphocyte count and T, B, and third population cells were comparable in both groups. Tγ cell proportions were significantly (p <0.001) increased in aging subjects when compared with the young subjects. However, this difference was more significant (p <0.001) when aged females were compared with the young females as compared to aged males vs young males (p <0.05). When data were analyzed for absolute numbers of Tµ and Tγ cells, a similar significant decrease in Tµ and increase in Tγ cells were observed. Interestingly, when these data were analyzed according to gender, significant differences in Tµ and Tγ cell numbers were observed between young and old females but not between young and old men. Implications of these results are discussed.