The article deals with peculiarities of allergic diseases (bronchial asthma, pre-asthma, pollinosis) in patients who were exposed to the factors of radiative, catastrophe. Screening--questionnaire was made on 381 patients who went through the Chernobyl disaster. 46 patients from this number who had various allergic diseases were chosen for specific diagnostics and immunological researches. A conclusion was made that critical systems of organism, and especially the immune systems had the major significance for the development and outcome of radiative injuries. The disorders in these systems contribute to the development of allergic diseases.