Autoimmune polyglandular syndrome represents a set of rare autoimmune diseases that affect two or more endocrine or non-endocrine organs. Based on the combinations of its component diseases, mode of inheritance, and age of onset, it is divided into three main types, i.e. autoimmune polyglandular syndrome type 1 and type 2, and IPEX syndrome. Autoimmune polyglandular syndromes type 1 and IPEX are monogenic diseases caused by mutations of the AIRE and FOXP3 genes, respectively, and almost always begin in childhood. Autoimmune polyglandular syndrome type 2 is a polygenic disease associated with mutations in the HLA system, and it usually appears in middle age, and rarely in childhood or adolescence. Different immunological, genetic, and environmental factors, which are responsible for the colorful clinical picture that characterizes the syndrome, and the variations between genotypes and phenotypes, play a role in their pathogenesis. In addition to the typical one, some patients present an atypical or subclinical picture of the syndrome, therefore the diagnosis of autoimmune polyglandular syndromes is often established by detecting specific autoantibodies and genetic testing for mutations. The diagnosis can be complemented by tests that give an insight into the function of the affected organs, and which are essential for assessing the degree of their damage. The treatment is carried out with hormonal replacement, it aims at the suppression of symptoms and the prevention of the complications of the disease and should be strictly controlled. Therefore, the cooperation of a multidisciplinary team is necessary to provide the best possible care to patients with diagnosed autoimmune polyglandular syndrome.