Aim. The aim of the study was to find genetic markers which can have influence on susceptibility of paranoid schizophrenia and the treatment efficiency measured by the PANSS (Positive and Negative Syndrome Scale). We analysed the gene polymorphisms: dopamine receptor - DRD2 (Tag 1A, in egzon 8, - 141 C ins/del), dopamine transporter - DAT, kainate receptor - GRIK3, serotonine transporter - SERT, serotonine receptor 5HT2A, mono amine oxidase A - MAO-A, catechol O-methyl transferase - COMT. Method. One hundred four Polish patients with the diagnosis of paranoid schizophrenia were recruited as the study group. To obtain the diagnosis meeting the ICD-10 criteria, we used the Polish version of CIDI - Composite International Diagnostic Interview. Exclusion criteria included serious neurological disorders, major somatic disorders impairing cognitive functions and diagnosed mental impairment. The intensity of psychopathological symptoms was examined using the PANSS. Genomic DNA was extracted from leucocytes using the Miller's salting method. Polymorphisms were studied by the PCR (Polymerase Chain Reaction) method using RFLP (Restriction Fragments Length Polymorphism) and VNTR (Variable Number Tandem Repeat) technique. Statistical analyses were performed by the Statistica computer program, specifically Pearson's chi-square test. Associations between the treatment progress and the genotype were studied by analysis of variance (ANOVA). Results. We did not find associations between investigated gene polymorphisms and susceptibility of paranoid schizophrenia. Probably, there is no influence of studied polymorphisms on the treatment efficiency. Conclusions. No differences were found in the genotypes distribution in the studied gene polymorphisms between the whole schizophrenics and the control group. No association was found between any particular genotype and the effect of antipsychotic treatment.