Infants hospitalized for bronchiolitis associated with respiratory syncytial virus are isolated for the duration of their hospitalization. This article reviews whether a negative rapid antigenic test could be used to shorten the duration of isolation measures. Rapid respiratory syncytial virus tests were performed from day 3 on alternate days in all patients hospitalized for bronchi-olitis. Isolation measures were removed when the test result was negative. The result of the antigenic test was confirmed by viral culture and polymerase chain reaction. Surveillance of nosocomial cases was performed daily. Forty-one patients were analyzed. On day 3, 51.2% of patients were negative by viral culture and 56.1% were negative by rapid testing. On day 5, a further 26.8% were negative by viral culture and 31.7% by rapid testing. The rapid antigen test had a low sensitivity at 60% and a specificity of 76% compared with viral cultures; therefore this test alone cannot be used to lift isolation measures.