We evaluated an enzyme-linked immunosorbent assay test (Adenoclone) for the rapid diagnosis of adenovirus infection in 589 cases of acute follicular conjunctivitis. Of 255 cases of adenoviral conjunctivitis proven by positive virus isolation. Adenoclone was positive in 51.0% by visual determination and 40.4% by spectrophotometry. Twenty-seven of 130 cases giving visually positive results were interpreted to be negative by spectrophotometry. In 334 adenovirus-negative cases, Adenoclone was negative in 99.1% and 99.4 by visual and spectrophotometric determination, respectively. Adenoclone was less sensitive in cases of adenovirus 3, 4 or 37, infections than in those of adenovirus 8, and also showed lower sensitivity in cases presenting mild conjunctivitis. Adenoclone is a rapid and easy test with high specificity but low sensitivity, and thus the test seems to be helpful in diagnosing adenoviral conjunctivitis.