Poorly controlled severe asthma can lead to growth impairment in childhood. In children with mild asthma, it is less clear whether treatment influences growth or adrenal function. We determined in a randomized, double-blind, placebo-controlled, community-based study, the effect of inhaled beclomethasone dipropionate (BDP) 400 micrograms/day for 7 mo on the linear growth and adrenal function of 94 children 7 to 9 yr of age. Height was measured at least monthly during treatment, and adrenal function assessed by overnight urinary cortisol at baseline and after 3 and 6 mo of treatment. Mean regressed daily growth was significantly decreased during the treatment period in the BDP-treated group, 0.79 versus 1.14 mm/wk (difference 0.35 mm/wk; 95% CI -0.46 to -0.25; p < 0.0001). At the end of the 7 mo, the BDP-treated children had grown significantly less than the children on placebo: mean of 2.66 versus 3.66 cm (difference 1.0 cm; 95% CI -1.36 to -0.64 cm; p < 0.0001). Growth was significantly decreased in both males and females. During a washout period of 4 mo, there was no significant catch-up growth. BDP had no effect on overnight urinary cortisol production. BDP at a dose taken by many children significantly decreases statural growth in children with mild asthma, and this effect is unlikely to be mediated through the hypothalamo-pituitary-adrenal axis.