Ozonated autohemotherapy is a controversial but successful method of treatment, used in particular in European countries. There are many fields in which medical ozone could be of value: treating different infections, immunodeficiency syndromes, neoplasms. Encouraging results have also been achieved in the treatment of atherosclerotic ischemia of the lower limbs. In this preliminary study, the influence of blood ozonation on the intensity of symptoms of ischemia of the lower extremities was analysed among dialysed patients with chronic renal failure. We examined 5 hemodialyzed patients and 7 patients treated with peritoneal dialysis immediately before and after 14 sessions of ozonated autohaemotherapy. Eleven patients (91.6%) reported a subjective decrease in perceived intensity of ischemic pains, or observed prolongation of intermittent claudication distance. During march tests performed on a treadmill, we found significant prolongation of intermittent claudication distance in all examined patients - 65.6% (mean value, p (< or =0.01). Patients treated with peritoneal dialysis achieved much greater improvement than did hemodialyzed patients (165% vs. 42%). We concluded that autohemotherapy with ozone, in a concentration of 34.4 mcg/ml of blood, is safe, easily applied and may be useful In the therapy of atherosclerotic ischemia of lower extremities among dialyzed patients. It could also be a complement to current treatment, especially in cases where the latter has failed.