The prevalence of antibodies to some bovine viruses of the respiratory and digestive systems were investigated in two caribou herds in Northern Quebec, Canada, in autumn of 1978 in one herd, and 1979 in another herd. The serum neutralization and hemagglutination inhibition techniques were used. Antibody to bovine viral diarrhea was the most prevalent in the two years (69.3% in 1978 and 60.7% in 1979), followed by bovine adenovirus 3 (42.9% and 17.8%), infectious bovine rhinotracheitis virus (39.6% and 14.2%) and coronavirus (13.3% in 1978 only). Antibody to parainfluenzavirus 3 was not detected.