Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive diseases characterized by a defect in one of the enzymes or transport proteins involved in the cortisol synthesis in the adrenal cortex. The most common form of CAH, which occurs in more than 90% of cases, is a 21-hydroxylase enzyme deficiency. The latter is subdivided into nonclassical and classic (salt-losing and virilizing) forms. The prevalence of classic forms of 21-hydroxylase deficiency ranges from 1: 14,000 to 1:18,000 live births worldwide. According to the data of neonatal screening in the Russian Federation, the prevalence of the disease in some regions ranges from 1: 5000 to 1: 12000, in the country as a whole - 1: 9638 live newborns. The non-classical form of CAH occurs more often - from 1: 500 to 1: 1000 among the general population. In second place is the hypertensive form of CAH - a deficiency of 11β-hydroxylase, which, according to the literature, occurs in about 1 per 100,000 newborns. These clinical guidelines were compiled by a professional community of narrow specialists, approved by the expert council of the Ministry of Health of the Russian Federation, and updated the previous version published in 2016. The clinical guidelines are based on systematic reviews, meta-analyses and original articles, and scientific work on this issue in the Russian Federation and other countries. The purpose of this document is to provide clinicians with the most up-to-date, evidence-based guidelines for the CAH diagnosis and treatment