To assess risk factors of recurrent bronchial obstruction and allergic sensitization 3 years after an episode of acute bronchiolitis, whether after ambulatory care treatment or hospitalization. A monocentric prospective longitudinal study including infants aged under 1 year with acute bronchiolitis was performed, with clinical (severity score), biological (serum Krebs von den Lungen 6 antigen), and viral (14 virus by naso-pharyngeal suction detection) assessments. Follow-up included a quaterly telephone interview, and a final clinical examination at 3 years. Biological markers of atopy were also measured in peripheral blood, including specific IgEs towards aero- and food allergens. Complete data were available for 154 children. 46.8% of them had recurrent wheezing (RW). No difference was found according to initial severity, care at home or in the hospital, respiratory virus involved, or existence of co-infection. A familial history of atopy was identified as a risk factor for recurrent bronchial obstruction (60% for RW infants versus 39%, P = 0.02), as living in an apartment (35% versus 15%, P = 0.002). 18.6% of the infants were sensitized, with 48.1% of them sensitized to aeroallergens and 81.5% to food allergens. Multivariate analysis confirmed that a familial history of atopy (P = 0.02) and initial co-infection RSV-hRV (P = 0.02) were correlated with the risk of sensitization to aeroallergens at 3 years. Familial history of atopy and RSV-hRV co-infection are risk factors for recurrent bronchial obstruction and sensitization.