The genome of bovine viral diarrhea virus (BVDV) contains a single large open reading frame capable of encoding 449 kDa of protein. Short segments from along the length of the molecularly cloned BVDV genome were engineered so as to be expressed as bacterial fusion polypeptides in Escherichia coli. These BVDV analog fusion proteins were used as immunogens to generate a panel of sequence-specific antisera. These antiserum reagents were in turn employed in immunoprecipitation analyses to identify the authentic BVDV protein to which they were directed. The results allowed for the identification and positioning along the genome of BVDV gene products accounting for approximately 83% of the coding capacity of the virus. A preliminary map of the genetic organization of BVDV is presented and discussed.