Patients with cystic fibrosis (CF) experience repeated infectious respiratory exacerbations leading to a continuous decline in lung function. The exacerbations are treated in hospital or at home. Our aim was to compare the clinical outcome for patients undergoing intravenous antibiotic treatment either in hospital or at home. A retrospective 10-year study was performed in four regional CF Centers. The outcome measures were percentage changes in forced expiratory volume in 1 sec (FEV(1)), forced vital capacity (FVC) and weight for age z-score (WZS). FEV(1), FVC, and WZS changes were calculated for the entire study period and for each course. A total of 1,164 courses were analyzed. For each course, the mean improvement in FEV(1) and FVC was significantly higher when performed in hospital than when performed at home (P < 0.05). FEV(1) and FVC values were 10.2%, 9.5% respectively in the hospital group and 7.3%, 6.8% in the home group. A total of 153 patients were analyzed (51 inpatients matched to 102 patients treated at home). The two groups had no significant differences in any outcome variable at baseline. The mean variation per year in FEV(1) was greater in the hospital group versus the home group (-0.4% vs. -1.8%; P = 0.03). The mean variation per year in WZS was greater in the hospital group versus the home group (P < 0.01). Clinical outcome, as defined by spirometric parameters and body weight, was better after a course of treatment in hospital than after a home treatment. This benefit was maintained throughout of the study period.