Background and Objectives: High intensity exercise weakens the immune system and causes upper respiratory tract infection (URTI). Probiotic supplements reduce the incidence of infections. In the present study, the effect of 8-week high-intensity intermittent training along with probiotic yogurt consumption, was investigated on immune cells, CRP, and IgA in young football players.Methods: In this quasi-experimental and applied study, 36 healthy young men (16 to 19 years) were randomly divided into two groups of supplement–training (ST) and training (T), with a mean height of 172±0.77 cm, weight of 66.76±5.87, and BMI of 21.27±2.09. Fasting blood samples were taken before and after 8-week training and after aerobic and anaerobic capacity tests. The subjects performed three 90-minute sessions of training, and the experimental group had probiotic yogurt (400ml) twice a day. Data were analyzed using Mann-Whitney-U test and repeated measurements at the significance level of p>0.05.Results: After training program, in the experimental group, lymphocytes, neutrophils, IgA, and C-reactive protein significantly increased, and no URTI case was observed.Conclusion: The results of this study indicated that training and consumption of probiotic supplement improve aerobic and anaerobic capacity and strengthen, immune system, and reduce the risk of URTI in ST group, therefore its daily consumption is recommended in athletes who perform intense physical training.