Autoimmune polyglandular syndromes (APS) are an autoimmune involvement of two or more endocrine glands, which are characterized by multiple organ dysfunction. Four major types of APS are presently identified. There are APS types 2, 3, and 4 in adults. There are also latent and incomplete forms of adult-onset APS, the prevalence of which in the population is well above that of clinically apparent diseases. Latent disease may strongly affect the compensation and risk of complications of the underlying condition. The examination of APS risk-group patients includes the detection of genetic (HLA Class II haplotypes, CTLA-4, PTPN22, and FOXP3 genes, etc.) and immunological (antibodies) markers in autoimmune diseases and the determination of the residual function of the target organ. The treatment of autoimmune diseases in adult-onset APS is based on general principles; however, there are a number of specific features of using drugs for the concurrence of a few endocrine diseases. In this connection, the timely identification of risk groups for developing the clinical forms of APS in patients with one autoimmune endocrine disease.