This review provides data on the most common primary immunodeficiency of the humoral immunity – the general variable immunodeficiency, the characteristics of the clinical manifestations of this pathology, as well as the features of diagnostics and treatment. The disease can develop at any age. However, around the world there is a late diagnostics of primary immunodeficiencies. The disease is characterized by a polymorphic nonspecific picture including lesions of almost all body systems. Infectious pathology and oncological diseases are the main cause of death in this group of patients. Early detection of patients with general variable immunodeficiency and the prescription of IVIG replacement therapy will increase the duration and improve their quality of life.