Phacomatoses are a diverse group of genetic disorders that primarily affect the central nervous system, skin and other organs. Most commonly, dysfunction of the central nervous system is the prevailing clinical manifestation of phacomatoses. Neuroimaging is therefore of great importance in treating these patients. In the article, we describe a case of a patient with neurofibromatosis type 2 and a case of a patient with von Hippel-Lindau disease. We discuss the role of magnetic resonance imaging in the diagnosis, follow-up and treatment of these disorder. Also emphasized is the importance of magnetic resonance imaging in screening of asymptomatic gene carriers and in their long-term suverillance.