CPIV-2 and CAY-2 antigens were prepared by the multiplication of the viruses in Vero and MDCK cell lines. Two hundred and ninety sera, including 45 sera collected from dogs under 3 months of life, were tested by the hemagglutination inhibition test (HI). 34.3% out of 245 adult dog sera reacted with CPIV-2 and 31.8% reacted with CAV-2. The percentage of animals seropositive to CPIV-2 and CAV-2 among young dogs was 42.2% and 48.9%, respectively. The HI titres with CPIV-2 ranged from 40 to 160, and with CAV-2 from 10 to 80.