Technical Abstract: A unique pestivirus, isolated from a blind pronghorn antelope (Antilocopra americana), was characterized. Antigenic analysis using polyclonal and monoclonal antibodies raised against bovine viral diarrhea genotype 1 (BVDV1) and bovine viral diarrhea genotype 2 (BVDV2) suggested this virus was antigenically related but distinct from both BVDV genotypes. Genomic characteristics, unique to pestiviruses, indicated that this virus belongs to the Pestivirus genus. These characteristics included the organization of the 5' untranslated region (UTR), the presence and length of a viral N**pro coding region, conservation of predicted amino acid sequences flanking the cleavage sites between viral polypeptides N**pro and C and between C and E**rns and conservation of predicted hydrophilicity plots of N**pro protein. While this data indicated the virus belongs to the pestivirus genus, phylogenetic analysis suggested that it is the most divergent of the pestiviruses identified to date. Comparison of predicted N**pro amino acid sequences of viruses from recognized pestivirus genotypes showed similarity values that ranged between 67.3% to 75.6%. Similar comparisons between the pronghorn virus sequence and representative viruses from the six recognized pestivirus genotypes yielded similarity values that ranged between 55.4% and 61.3%. These results suggest the virus isolated from pronghorn antelope represents a new pestivirus species and the first member of a new pestivirus genotype. It also represents the only pestivirus genotype first isolated from New World wildlife.