The avidin-biotin-peroxidase complex (ABC) technique was used to detect avian reovirus (ARV ) antigen in chickens inoculated with ARV via three routes. The test results suggested that the viral antigen wat widely distributed in the visceral parenchymal organs, intestinal tract, tendon sheaths and synovial membranes. Except for the tendon sheaths and synovial membranes, viral antigen was not detected 4 weeks after inoculation, but these two tissues still showed positive results when the 60-day experimental perkid terminated. No positive ABC staining was observed in the blood cell smears of infected chickens. The ABC method was more sensitive than vims isolation.