Physically active lifestyle affords healthier life while sessile way of life reduces quality of life. Many different factors may change the immune functions: young or elderly people, chronic diseases or exhausted people and person after intensive physical exertion. Exercise-induced factors such as oxidative stress, increased metabolic rate, heat shock proteins, catecholamine, cortisol and insulin-like growth factor can influence pathogen recognition by altering expression of recognition molecules such as Toll-like or scavenger receptors, cell trafficking by altering hematopoiesis, cell death and adhesion molecule expression. Some evidence has shown that athletes included in heavy training programs were susceptible to infection. Regulatory T cells (Tregs) play a crucial role in peripheral T-cell tolerance. Tregs represent a subpopulation of suppressor T cells that mediate immune tolerance by suppressing autoreactive T cells. Immune system’s capacity to distinguish between innocuous and harmful foreign antigens is controlled by mechanisms of central and peripheral tolerance. Mechanisms of peripheral tolerance involve induction of cell death or the development of a non-responsive state (anergy) of T cells. Lymphatic cells could be stimulated to release perforin causing induction of apoptosis. An important mechanism for activation of Tregs is by immature dendritic cells. The aim of this study was to investigate the percentage of innate immune cells and perforin positive cells in lymphocyte subpopulations of peripheral blood of professional athletes. Subjects were selected from a stratified population sample of adults of both sexes during a routine examination of professional athletes, as well as, with “recreational” or noncompetitive athletes. The study was approved by the ethical committee and all study subjects gave their written informed consent. The phenotypic profiles of peripheral blood lymphocytes were done by flow cytometry. Our preliminary data showed that the percentage of cells of innate immunity: NK (CD3-CD56 +), NKT (CD3 + CD56 +) and regulatory T cells (Tregs: CD4+CD25+FoxP3+) in professional athletes compared with healthy controls and noncompetitive athletes were significantly elevated in professional athletes. Total perforin positive cells and double positive (perforin+ NK+cells) in professional athletes were increased in comparison with blood donors. Percentage of B cells was increased in trained athletes. Intensive physical activity in professionally trained athletes had a positive impact on immune response, particularly intensive in innate immunity, which is the first line of defense in the body against the effects of adverse factors. Tracking changes in the percentage of T regulatory cells may contribute to better understanding the interdependence of hormonal and immunological network during physical activity.