Rendu-Osler-Weber disease (hereditary hemorrhagic telangiectasia) is a rare hereditary disease that develops in childhood, characterized by vascular dysplasias, multiple telangiectasias of the skin and mucous membranes, and hemorrhagic syndrome of different localization. One of the first and most noticeable signs of the disease is spider veins on the skin and nasal mucous membranes. With lesions of nasal mucosa and gastrointestinal tract, the disease proceeds with frequently recurring bleeding. In chronic blood loss, iron deficiency anemia develops, and in acute cases, a fatal outcome is possible. The article provides a brief historical summary of Rendu-Osler-Weber disease description, etiopathogenetic mechanisms of the disease development, clinical picture with the most typical manifestations, as well as modern diagnostic and treatment criteria. Particular attention is paid to the early diagnosis of the disease. In conclusion, the authors cite their own observation of an 11-year-old patient with Rendu-Osler-Weber disease. © 2019, Pediatria Ltd. All right reserved.