After the first wave of new coronavirus infection caused by SARS-CoV-2, when it became obvious that children carry COVID-19 in a milder form than adults, scientists and doctors around the world faced with a severe delayed form of the disease – SARS-CoV-2-associated multisystem inflammatory syndrome (MIS), characteristic for children and young adults under 21. In this publication authors present the first case of SARS-CoV-2-associated MIS of moderate severity in an 8-year-old girl diagnosed in Khimki Regional Hospital. Disease course had characteristic features, however, considering minimal data available at the time of the child's treatment in the hospital (May 2020) in the literature, and lack of clinical experience in diagnosing and treating such condition, the differential diagnosis was performed with acute respiratory disease, infectious mononucleosis and acute glomerulonephritis.