Cognitive deficit is a key feature of schizophrenia. Genetic factors are thought to contribute to cognitive disturbances in schizophrenic patients. However, the role of specific genes in the development of cognitive deficit remains elusive. The review considers the current studies on the association between gene polymorphisms and cognitive dysfunction in schizophrenics. Main attention is drawn to the consistently reproducible association between the COMT polymorphism Val158Met and cognitive traits, which has a biological and neuropsychological support. The association studies with the genes for the dopamine and serotonin receptors, brain-derived neurotrophic factor, dysbindin, DISC1, D-amino acid oxidase, and D-amino acid oxidase activator are reviewed as well.