An improved staphylococcal coagglutination test was developed for rapid detection, in a single assay, of rotavirus and adenovirus in stool samples (COARA). Suspensions of Staphylococcus aureus coated respectively with anti-rotavirus and anti-adenovirus sera were used to identify these viruses in 327 stool samples of children. The samples were also tested by an enzyme immunoassay. The data analysis has demonstrated a high degree of correlation between the two assays.