Beclomethasone dipropionate inhaled as a dry powder in doses of 200 microgram four times a day was compared with the usual dose of 100 microgram four times a day from a pressurized aerosol in 65 patients with asthma who used pressurized aerosols correctly. Each treatment was given for an eight-week period. The dry powder did not show any clinically significant advantage over the aerosol in terms of ventilatory function as measured by FEV1 and the daily peak flow measurements during both treatments did not differ. The incidence of oral candidiasis was low and no other side-effects were encountered. It was concluded that beclomethasone dipropionate in dry powder form was as effective as aerosol in the treatment of asthma.