Meningococcal infection remains a socially significant disease due to a wide range of clinical manifestations, severe course with high mortality, reaching 40-80% for certain forms. In recent years we observe a change in the serogroup picture of meningococcal infection, in particular, an increase in the proportion of meningococcal serogroup W, characterized by polymorphism of clinical manifestations. The authors present two their own clinical observations of a generalized form of meningococcal infection with a severe course in adolescents caused by Neisseria meningitidis of W serogroup with fatal outcome. They describe the peculiarities of the cases, namely, inconsistency of the clinical picture at the beginning of the disease and post-mortem changes. The article describes heart damage in the form of focal purulent septic myocarditis and purulent foci of destruction in the brain stem, hemorrhagic infarction of the choroid plexus with hemotamponade of the lateral ventricles of the brain, the predominance of septicopia over septicemia. The revealed changes are likely to reflect clinical and morphological features of meningococcal infection caused by N. meningitidis of serogroup W.