Aims: The influence of acute ozone (O3) exposure on the tissue oxidant/antioxidant (O/AO) balance in the brain, myocardium, lungs and striated muscles was studied at rest and during exercise. Material and Methods: The research was performed in 3 groups of white male Wistar rats with a weight of 280-300 g: Group I – control group, sedentary rats under normoxia conditions; Group II – sedentary rats, acutely exposed to O3; Group III – animals acutely exposed to O3, followed by exercise under normoxia conditions. The rats were exposed to ozone for 3 days, 5 min/day. Group III was trained daily for 3 days under normoxia conditions by the swimming test. In order to determine the indicators of the oxidant/antioxidant balance, tissue samples from the brain, myocardium, lungs and quadriceps muscle of the anesthetized animals were taken. On the third day the following were measured: malondialdehyde (MDA), protein carbonyls (PC), hydrogen donor capacity (HD) and total sulfhydryl (thiol) group content (SH). Results: Between the indicators of the tissue O/AO balance, significant correlations were evidenced in the brain, myocardium, lungs and muscles. Conclusions: Acute combined stress through O3 pre-exposure and exercise causes OS on account of PC in the brain, myocardium and muscles, a decrease in AO defense capacity on account of HD in the brain, lungs and muscles, and an increase in AO defense capacity in the myocardium.