Background/Aim. Oxidative stress is a state of disturbed balance between reactive oxygen species (ROS) and reactive nitrogen species (RNS) on the one hand, and antioxidative defense on the other. As a result of oxidative stress we have irreversible changes in cell function leading to pathological tissue changes, development of many diseases and fast aging process. Increased consumption of oxygen during exercise could be the cause of oxidative stress. The aim of the study was to establish oxidative status of elite karate athletes in the state of rest and after the loading, monitoring the parameters of oxidative stress and components of antioxidative defense in a treaining process. Methods. During training process, a group of 30 elite karate athletes was included in the study of prevalence. They were males, from 16 to 30 years of age. The examination was conducted both in resting condition and after the loading. Oxidative status was determined by the level of superoxide anion radical (O2-), hydrogen peroxide (H2O2) as prooxidants, and enzymes of the antioxidant defanse system: superoxide dismutase (SOD) and catalase (CAT). Results. There was a homogenous group of young athletes of normal weight and fats percentage. A significant decrease of O·2- after the load was founded, while the levels of H2O2 was significantly increased. Activity of SOD was not significantly changed after exsercise while that of CAT was significantly increased. Conclusion. In the long run a programmed physical exercise does not lead to oxidative stress, but an excessive physical load may cause its occurrence.