In France, surveillance of bronchiolitis is based on a pilot network of hospital emergency departments. The study was a 1-year observational study (2007-2008) carried out in a central region of metropolitan France. The hospitalization rate for bronchiolitis was 17.7/1000 children aged <1 year and the estimated prevalence of bronchiolitis ranged from 17.7% to 34.4% in children aged <1 year. Such a network constitutes a valuable tool to estimate the dynamic and the burden of infant bronchiolitis. (R.A.)