Exercise is one of the most powerful non-pharmacological strategies, which can affect nearly all cells andorgans in the body. Changes in the behavior of adult stem cells have been shown to occur in response to exercise.Exercise may act on regenerative potential of tissues by altering the ability to generate new stem cells and differentiatedcells that are able to carry out tissue specific functions. The purpose of this study was to reveal the role of aerobic andanaerobic training programs on CD34+ Stem Cells and chosen physiological variables. Twenty healthy male athletesaged 18-24 years were recruited for this study. Healthy low active males and BMI matched participants (n=10) aged20-22 years were recruited as controls. Aerobic and anaerobic training programs for 12 weeks were conducted.VO2max pulse observation was carried out using the Astrand Rhyming protocol. RBCs, WBCs, HB and hematocritwere estimated using a coulter counter, lactate by the Accusport apparatus, CD34+ stem cells by flow cytometry.VO2max was increased significantly in case of the aerobic training program compared to anaerobic one (62±2.2ml/kg/min vs. 54±2.1 ml/kg/min). Haemotological values increased significantly in the anaerobic program whencompared to the aerobic one, RBCs (5.3±0.3 and 4.9±0.2 mln/ul), WBCs (6.6±0.5 and 6.1±0.4 thous/ul), HB (15.4±0.4and 14.2±0.5 g/de), Hematocrit (4.6±1.2 and 4.4±1.1 %), CD34+ stem cells count increased significantly in case of theanaerobic program compared to the aerobic (251.6±21.64 and 130±14.61) and sedentary one (172±24.10). Thesefindings suggest that anaerobic training programs provoke better adaptation to exercise and stem cell counts may differbetween trained and sedentary subjects. Circulating immature cells are likely to be involved in angiogenesis and repairprocess, both mechanisms being associated with strenuous exercise. Knowledge of the physiological effects of training onstem cells might be of potential clinical use.