The authors reviewed the history of the development of diagnostics and treatment of an incurable disease as a primary immunodeficiency. This disease is an urgent and complex problem, a challenge for modern clinical medicine. On the one hand, it is classified as rare, hence the difficulty in diagnosis. On the other hand, this disease has many people - a very high variability of its clinical manifestations. The disease makes its debut most often in childhood, even in early infancy, however, specialists working with this group of patients do not have sufficient competencies to identify it or have not met with this disease at all. Hence another complication - the temporal gap between the onset of the disease and its adequate diagnosis. The history of the emergence of knowledge about primary immunodeficiencies is only a few decades old. The article discusses the problems of diagnosis and provision of medical care to patients with primary immunodeficiency, they are associated with insufficient information about the disease. In various countries of the world, on the basis of research institutes or medical centers, scientific groups are being created to study these diseases, systematize information about them, including through the creation of registers of these patients. Only joint efforts at the national and international level can help patients.