Our aim was to study polymorphisms of the <i>BDNF</i> gene and serum levels of BDNF in schizophrenia and to analyze the concentration of this marker depending on clinical and genetic characteristics.<h4>Methods</h4>A clinical and biological examination of 123 patients with paranoid schizophrenia (F20.0, ICD-10) was conducted. The gene discussed is BDNF; the disease is schizophrenia.