Inhaled steroids improve pulmonary function and bronchial responsiveness in older asthmatics. Data from studies using subjective outcome measures to determine the effectiveness of inhaled steroids in infants with recurrent wheezing are equivocal. Therefore, this study tested the hypothesis that beclomethasone dipropionate improves pulmonary function, including bronchial responsiveness to histamine, in recurrently wheezy infants. The study was double blind, placebo controlled lasting nine weeks. After the first baseline week, pulmonary function was measured using the rapid thoracoabdominal compression technique and bronchial responsiveness assessed with a histamine challenge test. Infants were then randomly allocated to receive doses of placebo or beclomethasone dipropionate (100 μg/puff) from metered aerosols. Two puffs of test aerosol were administered twice daily for eight weeks via a large volume spacer fitted with a facemask. Symptoms were recorded daily and pulmonary function and bronchial responsiveness assessed at the end of the treatment period; 50 infants, median age 12 months (range 5 to 18 months), were recruited. Twenty three in the beclomethasone dipropionate group and 15 in the placebo group completed the study and had pairs of pulmonary function measurements. Three were probable treatment failures (one beclomethasone dipropionate, two placebo), three were possible treatment failures (placebo), and others were non-compliant with study protocol. Baseline variables were not significantly different between those Australia infants who completed the study and those who did not. Beclomethasone dipropionate and placebo groups were similar in all respects at baseline. Lung function and improved for both groups during the study. Bronchial responsiveness increased significantly in the placebo group but there were no statistically significant differences between groups for any of the other outcome measures. It is concluded that beclomethasone dipropionate (400 μg daily) via a large volume spacer does not significantly improve lung function or symptoms in recurrently wheezy infants but might have a beneficial bronchial responsiveness.