It has been found that the effect of whole-body gamma-irradiation with doses of 10 and 150 Gy on the haemodynamics regulation varies. Thus, the dose of 10 Gy does not change the arterial tension and the dose of 150 Gy decreases the arterial tension 6 and 24 hr after irradiation, the nociceptive reactions of haemodynamics being invariable with both doses.