In this multicenter, randomized, double-blind study comparing the efficacy and safety of aerosolized albuterol with the dry powder formulation, 231 patients with chronic reversible obstructive airway disease were randomly allocated to receive either placebo albuterol aerosol followed immediately by active albuterol powder (200 micrograms) or active albuterol aerosol (two puffs, 180 micrograms) followed immediately by placebo lactose powder four times a day for a period of 12 weeks. No statistically significant differences were found between the powder and aerosol formulations with respect to pulmonary function, length of time mean FEV1 remained greater than or equal to 15% above baseline, physicians' assessments of patients' clinical response, or patients' subjective symptom scores. There were also no significant differences between treatment groups in cardiovascular effects, laboratory values, or adverse events. Among patients who expressed a preference for one of the delivery systems, half preferred using the powder. Results of this study demonstrate that 200 micrograms of albuterol powder is as safe and effective as 180 micrograms of albuterol aerosol.