Borna Disease Virus (BDV) is single stranded RNA virus, which may infect a wide range of animal species. Manifestations of the experimental BDV infection show some resemblance to psychopathological symptoms of mental disorders in humans. Several reports suggest the higher prevalence of anti-BDV antibodies in psychiatric patients than in healthy controls. However, the seroprevalence of anti-BDV antibodies varied due to the different serological methods used in the previous studies. Electrochemiluminescence Immunoassay (ECLIA) is a recently developed, highly specific method of detecting antibodies directed toward two BDV proteins: p24 and p40. We used the ECLIA method for the assessment of seropositivity in 946 psychiatric patients hospitalized in the psychiatric hospitals in the western part of Poland. All patients were clinically diagnosed with ICD-10 criteria. Anti-p40 antibodies have not been found in the studied sample. We found anti p-24 antibodies in 23 cases, which give the seroprevalence rate of 2.4%. This result is consistent with the outcome of Japanese population assessment, done with the same methodology. The seropositive cases did not show diagnostic specificity. We did not find statistically significant gender differences in rate of seropositivity. The seroprevalence of anti-BDV antibodies was not significantly different in patients of urban and rural residence, and in patients of different age groups. This is the first demonstration of anti-BDV antibodies in the Polish population of patients hospitalized in psychiatric hospitals.