The function of the hypothalamic-pituitary-adrenal (HPA) axis was investigated in nine asthmatic children treated by inhalation of beclomethasone dipropionate (300 micrograms/day) for 12 weeks. The trial was designed as a prospective study. The 24-hour urinary free cortisol, serum cortisol, response to ACTH, and nocturnal serum cortisol followed by 20-minute sampling were measured before and after the study period. No significant changes were found, suggesting that inhaled beclomethasone, in a daily dose of 300 micrograms, does not cause suppression of the HPA axis.