Serological tests and viral isolation procedures were carried out on 26 sick calves (6-10 months old) in an outbreak of respiratory-enteric disease which affected nearly all of 188 beef cattle within a 3-week period. Parainfluenza-3 virus was isolated from six calves, unidentified cytopathic agents were isolated from five calves, and five had a fourfold increase in titre to bovine diarrhoea virus. Infectious bovine rhinotracheitis (IBR) virus was not isolated, but three calves became serologically positive and one calf developed a fourfold increase in titre against that virus. An unidentified cytopathic agent was isolated from the calf which had a fourfold increase in titre to IBR virus. Three calves had evidence of dual infection with BVD and PI-3 viruses.