The aim of this study was to assess the diagnostic value of Peroxidase Linked Assay (PLA) for detecting the bovine leukemia virus (BLV) infection. Two negative and two positive reference sera were applied to 204 serum samples from dairy cows from 3 different farms (I, II and III). The best results of serological testing were obtained in the herd infected with BLV for several years (I). Amongst 10 serum samples taken at random, all were positive in AGID, ELISA and PLA. Serological tests of samples from group II revealed: 34 (73.9%) positive results in AGID and 39 (84.7%) either in ELISA or PLA. In group III positive results in AGID occured in 81.8% of cases, and 91.9% and 92.9% in ELISA and PLA respectively. The mean OD value for positive samples in groups II and III ranged between 0.943 and 0.215. Immunoperoxidase PLA is a specific and sensitive test for detection of BLV infections.