A 50 kDa cell surface protein from MDBK cells has been identified as a putative receptor for bovine viral diarrhea virus (BVDV) by using a BVDV specific anti-idiotypic antibody (Anti-D89). This study delineates further characterization of the receptor protein. Protease treatment of cultured MDBK cells adversely affected the receptor thus abolishing the binding of anti-D89 to the cells. However, pretreatment of the cells with either phospholipases or glycosidases did not signficantly alter the extent of anti-D89 binding. Additionally, pretreatment of cell monolayers with proteases decreased BVDV attachment and replication in the cells. These results suggested that the receptor for BVDV is a protein in nature, and glycosylation and phosphorylation of the receptor protein may not play a direct role in BVDV attachment to cells. The BVDV receptor protein gradually regenerated on cells when they were maintained in culture following protease treatment. The purified 50 kDa receptor protein also significantly inhibited BVDV infection in a plaque reduction assay.