The present study has demonstrated the expediency and effectiveness of the application of oxygen/ozone therapy during exacerbation of stage І-ІІ knee arthritis as evaluated based on the WOMAC index, VAS, and Lyshom scale within one and six months after the onset of the treatment. The resulting reduction in the number of days of temporary incapacity for work in the patients suffering from knee arthritis gives evidence of the clinical and economic validity of the proposed method of the combined treatment of this condition based on the application of oxygen/ozone therapy.