Objective. Until now the problem of the typical age of schizophrenia onset has been actively discussing in the world literature. Though there are more and more publications, which mention the growth in the number of cases with late-onset and very-late-onset of the disease, a conviction that schizophrenia is the illness of teenagers or young people is still exists. Author aimed to determine a preferable age of the onset of schizophrenia. Material and methods. Data obtained in multi-year epidemiological research in Mental Health Research Center (Moscow) were analized. The total number of patients with schizophrenia and spectrum disorders was 5486. A subgroup of the patients with the diagnosis that met the current diagnostic criteria of schizophrenia included 1108 people. The study was based on clinical-epidemiological and statistical methods. Results. Most of patients had early onset schizophrenia (16-20 years old maximum). However, it mostly depended on demographic factors, because more than half of patients were young or middle aged at the moment of the examination. The examination of the group aged over 60 years and those who conditionally belonged to this generation (if 100% would have lived to that age) showed that the maximum number of patients had onset between 30-40 years old. Conclusion. This research demonstrates the essential predominance of cases with onset of the disease in adolescent and young age that may be rather related with demographic characteristics than pathogenetic mechanisms of schizophrenia. The latter determine predominantly middle age of disease onset (30-40 years). Cases both with early and late onset of the disease are not rare and are random deviations from the mean valuation.