Altogether 1,500 healthy residents of seven cities situated in the Asian part of the USSR were examined. In Novosibirsk, Tomsk, Tyumen, Norilsk, Magadan, Yakutsk and Ussuriisk, the people were examined for the blood levels of T and B lymphocytes, the ratio of regulatory subclasses of T lymphocytes, the concentration of IgG, IgM and IgA, and for the content of immune complexes. Analysis was made of the general and regional regularities in changes seen in the immune system depending on climatic and geographic factors. Parameters of the populations similarity in the regions with different environmental conditions were delineated.