To examine the effect of eight weeks endurance exercise program on blood's TNFa, CD8, CD4, and IgA in active females. Twenty students of physical education participated in the study. Subjects were assigned in two groups: experimental group: (n=10) (age: 21.6±1.71 years, height: 161.45±2.71 cm, weight: 57.25±6.99 kg. and Vo2max 34.18±2 ml.kg¯¹.min¯¹) and control group: (n=10), (age: 24.25±4.30 years, height: 159.81±4.86 Cm, weight: 54.69±3.82 kg and Vo2max: 36.1±3.79 ml.kg¯¹.min¯¹). Blood samples of the students were obtained before and after an exhaustive session of exercise. Training group participated in an 8-week incremental endurance exercise program. After training, blood samples were obtained before and after an exhaustive session of exercise. Data was analyzed using ANOVA test. There were no significant changes in TNFa and IgA concentrations but CD4 and CD4/CD8 decreased and CD8 increased significantly (P£0.05). It was concluded that endurance exercise may induce changes in lymphocyte subsets but not in suppression of immune function after an exhaustive session of exercise and CD8 and CD4 functions adapted in experimental group. We conclude that endurance exercise may result in significant alteration in T lymphocyte number.