Aim. The aim of the work was to assess relationship between gene polymorphism of enzymes influencing dopaminergic-, serotoninergic, and noradrenergic transfer and cognitive functioning of paranoid schizophrenic inpatients (ICD-10). Method. The following methods have been used in the study: The Test of Everyday Attention (TEA) and The Visual Object and Space Perception Battery (VOSP), psychiatric scales (SAPS, SANS, BDI) and techniques of genetic engineering (PCR reaction, RFLP and VNTR techniques). Subject groups included 100 schizophrenic patients (57 male) and 50 healthy controls (20 male). Results. The results revealed positive correlation between polymorphism of Val158Met-COMT and cognitive deficits in schizophrenic patients. No statistically significant relationship was elicited between gene polymorphism of Val158Met COMT and VNTR MAO-A in promoter area and schizophrenia onset. Allelic polymorphism of Val158Met OMT and VNTR MAO-A in promoter area did not differ between the subject groups. The patients with genotype Val/Val of polymorphism Val 158MetCOMT showed major cognitive deficits.