A competitive enzyme-linked immunosorbent assay (ELISA) for detection of canine parvovirus (CPV) antigen in fecal samples was developed. Fecal samples were tested by ELISA and a direct hemagglutination assay, and the results compared. The tests gave the same results in 83% and 88% of the fecal samples, depending on whether the samples were treated with chloroform. The discrepancies were due to the fact that each test detected virus in certain fecal samples that was not detected by the other. The use of a monoclonal anti-CPV conjugate resulted in a highly specific test. The performance of the ELISA as a competitive assay also increased the reproducibility and sensitivity over that which could be obtained from a classic sandwich-type procedure.