Bronchiolitis is the most common lower respiratory tract infection in infants < 2 years of age; in the last decades both incidence and hospitalization rate had increased, thus increasing sanitary burden. From November 2006 to March 2007, an experimental protocol was followed in the Emergency Department at G. Gaslini Children's Hospital, Genoa, Italy, which attempted to optimise the management of patients with bronchiolitis and to reduce the overall hospitalization rate therefore admitting only those patients with severe illness. All clinical evaluations of the patients were obtained administering a score (Bronchiolitis Clinical Score - BCS), to quantify both initial severity of illness and response to treatment. All patient were at first treated with inhaled epinephrine, supplemented with or substituted by other drugs, if needed, according to clinical evolution. Moreover, strict admission and discharge criteria were defined, taking into consideration the BCS, response to treatment and the presence of risk factors for severe disease, attempting to increase the role of the Short Stay Unit (SSU). The outcome evaluated were the percentage of patients discharged, admitted and managed through the SSU respectively, the length of stay and the readmission rate after discharge; data collected were then compared to that regarding patients with bronchiolitis presented at the ED from November 2005 to March 2006. Our data showed an increasing of both discharged patients (37.5% vs 25.22%) and patients managed through the SSU (25.83% vs 19.57%) and a related decrease of hospitalization (36.67% vs 55.22%); no significative difference was observed regarding the readmission rate between the two populations. We also observed a statistically significant reduction of the length of stay in the study population (2.07 +/- 2.56 vs 2.84 +/- 3.25, p = 0.005). In conclusion, the protocol proposed showed to be useful in optimizing the ED management of the patient with bronchiolitis, being able to safely reduce both admission rate and lenght of stay.