Eighteen subjects with moderate asthma participated in this double-blind study comparing the bronchodilator response to albuterol or placebo used in conjunction with three inhalation devices; the metered dose inhaler (MDI) actuator alone, the AeroChamber, and the OptiHaler. The principal comparison was the increase in FEV1 over 30 minutes. Also recorded were heart rate, time required to use each device, and patient acceptance of each device. There was a large bronchodilator response with albuterol with each of the devices, but there was no difference in the promptness or the magnitude of the bronchodilator response among the three devices. There was a small but statistically significant increase in heart rate which did not differ among devices. Subject ratings of acceptability were MDI alone best, followed by OptiHaler, then AeroChamber. We conclude (1) the bronchodilator response obtained with use of the MDI alone, the AeroChamber and OptiHaler were not significantly different; (2) patients, as a group, found the MDI required less time to use and they favored it over either spacer; (3) while in subjects employing good MDI technique, the addition of either an AeroChamber or an OptiHaler did not improve bronchodilator response. Spacers may have a role in those with poor inhaler technique or in conjunction with inhaled corticosteroids.