The prevalence of bovine viral diarrhea (BVD) virus infection on the basis of serological testing of cattle has been evaluated. Blood samples were analyzed in micro-seroneutralization test for the presence of BVD virus neutralizing antibodies against 1000 TCID₅₀ of NADL reference strain. Neutralizing antibodies were found in 83 per cent of animals tested. The percentage of seropositive animals was directly correlated with the age of animals. These results can be linked with the circulation of the virus in the cattle population since vaccination against bovine viral diarrhea virus (BVDV) infection is limited to a very small scale in Poland.