The aim of this work was to test the effect of culturistic training and oral supplementation with L-carnitine on induced and spontaneous chemotaxis of granulocytes, chemiluminescence of granulocytes and intracellular expression of cytokines 11-2, IL-4, IFN-γ in lymphocytes. The tests were done before and after 5-week culturistic training of young males. One of the chosen at random groups received L-carnitine in a dose of 11.5 mg for 1 kg of body mass, the other one received placebo. It was stated that training increases spontaneous chemotaxis of granulocytes. Supplementation with L-carnitine only stimulated spontaneous chemotaxis of granulocytes derived from capillary blood, no significant differences were stated in other assays which points at a fact that L-carnitine administered in a dose of 11.5 mg for 1 kg of body mass through the period of 5 weeks does not produce unfavourable changes in the immune system of sportsmen and may exert immunomodulating influence.