Introduction. The geographical spread of patients with orphan diseases is a big problem in the diagnosis and treatment of these patients. Thus, the issue of spatial heterogeneity of the epidemic situation is relevant, in connection with the need to develop a unified approach to the identification of orphan diseases and a system of management decisions aimed at the availability and quality of medical care for patients with orphan diseases. Аim: to study the spatial heterogeneity of the epidemic situation for 11 orphan diseases in children 0-17 years old (in the context of their detection). Materials and methods. We studied indicators reflecting the spatial heterogeneity of the epidemic situation for 11 orphan diseases detailed in the form of federal statistical observation No. 12 "Information on the number of diseases registered in patients living in the service area of a medical organization" in the Russian Federation as a whole, as well as in the context of the constituent entities of the Russian Federation, over the past 5 years (2020 to 2024) - pituitary hyperfunction (code MKB-10 E22), hypopituitarism (E23.0), adrenogenital disorders (E25), phenylketonuria (E70.0), galactosemia (E74.2), Gaucher disease (E75.2), mucopolysaccharidoses (E76), cystic fibrosis (E84), multiple sclerosis (G35), Duchenne muscular dystrophy (G71.0), neurofibromatosis (Q85.0). Results. Differences in the primary incidence of orphans in the city and village are approaching one and a half times, and exceed the threshold of statistical significance for pituitary hyperfunction, neurofibromatosis, multiple sclerosis, adrenogenital disorders, which are diagnosed worse in the rural population. There are no differences in the incidence of urban and rural populations in phenylketonuria, galactosemia, Gaucher disease, mucopolysaccharidoses, cystic fibrosis. Most of these diseases are detected during standard newborn screening, which is the same for residents of the city and village. According to data on the detection of diseases during preventive examinations, rural residents have some problems with the coverage of neonatal screening, or with ensuring its quality. Thus, phenylketonuria was detected during preventive examinations in 17.1% of rural residents, while for urban residents this figure was 3.3% (p