Three various cases of cytomegalovirus infection will be described. At first will be represented a double infection of cytomegalovirus and toxoplasmosis. In the second case it's about the organmanifestation of cytomegalovirus of the liver as hepatitis. At last will be discussed a severe infection of the central nervous system on the one hand in form of Guillain-Barré-syndrome, on the other hand manifestated as encephalitis.