Objective: The MAGhaler (R) is a CFC-free, refillable inhalation device. The objective of this clinical study was to show equivalent efficacy and safety of beclomethasone dipropionate (BDP) delivered via MAGhaler (R) or via CFC-containing pressurized metered-dose inhaler (pMDI) in children with mild to moderate bronchial asthma. Usability and acceptance of the two devices were also compared. Methods: This was a double-blind, randomised, reference-control led, 12-week trial in 38 children with mild to moderate asthma receiving BDP (2 x 250 mu g/day) delivered via either the MAGhaler (R) (N - 19) or the pMDl (N = 19). Equivalence of the devices was assessed on the basis of the ratio (MAG/pMDI) of the mean forced expiratory volume in one second (FEV1) measured during therapy. In addition, the two-sided 90% Fieller confidence interval (Cl) for the ratio of means was calculated. Lung function parameters, clinical symptoms, concomitant intake of salbutamol or fenoterol, adverse events, and laboratory values were recorded. Results: In the per-protocol analysis (N = 35), the ratio (MAG/ pMDI) of mean FEV1 during therapy was 1.07 [90% CI (0.93; 1.24)] indicating that the two devices were comparable. Mean FEV1 increased from 2.00 +/- 0.451 (baseline) to 2.16 +/- 0.53 1 (week 12; MAG) and from 1.88 +/- 0.54 1 to 2.01 +/- 0.56 1 (pMDI). A total of 28 (80%) children preferred the MAGhaler (R) to the pMDI. The safety profile of BDP was similar in both groups. Conclusion: BDP administered via the MAGhaler (R) was as safe and efficacious as that delivered via the pMDI. The MAGhaler (R) was very well accepted.