Biochemical and immunological indexes of peripheral blood were compiled in military sanatorium "Divnomorskoe" in seamen who have suffered from general supercooling in the result of "Komsomolets" atomic submarine breakdown. The patients had the symptoms of metabolic disturbance, immunodepression, a great concentration of proteins in acute phase and activity of MB-fraction of creatine phosphokinase. Immunodepression after the general supercooling was mainly conditioned by oppression of differentiation, metabolic changes and functional activity of T-lymphocytes. A course of immunocorrective therapy was employed using "thymogen"--synthetic peptide of thymus. In the process of rehabilitation there was a gradual functional recovery, normalization of metabolism and immunological indexes.