The polarographic method using platinum electrode has been applied to study the effect of ceruloplasmin (CP) on the oxygen tension (pO2), oxygen saturation rate and rate of oxygen utilization in the muscular tissue of high-leukemic AKR mice, C57BL/6 mice with transplanted Lewis lung carcinoma (3LL) and rats after gamma-irradiation in a dose of 7 Gr. It has been shown that CP in AKR mice improves oxygen saturation of the muscular tissue. This effect is also evident in the case of the marked pO2 decrease in the muscle and its oxygen saturation rate (animals with Lewis lung carcinoma and after gamma-irradiation).