The optimal dose of salbutamol for testing spirometric reversibility in patients with chronic obstructive pulmonary disease (COPD) has not been determined and either 200 or 400 µg are commonly used. The purpose of the present study is to test both doses in a group of patients with mild to severe COPD. Forty stable COPD patients were included to receive in random order both doses of salbutamol, with spirometry being performed before and after 15 min of their administration. Absolute and percent predicted changes were evaluated. For the latter, an increase in forced expiratory volume in one second (FEV1), slow vital capacity (SVC), forced vital capacity (FVC) and inspiratory capacity (IC) equal or greater than 10% predicted was considered clinically significant. No differences were found in absolute post-bronchodilator values between the two doses. In addition, the proportion of responders to 200 and 400 µg of salbutamol according to the percent predicted changes was similar with both doses. This was particularly true when all variables related to volume changes (SVC, FVC, and IC) were included in the analysis. In conclusion, the present results indicate that for testing spirometric reversibility in COPD patients the 200 µg dose of salbutamol is as effective as the 400 µg dose