Background:A correct selection of drugs prescribed, but also the choice of the appropriate inhaler device, is crucial for the control of respiratory diseases.Objective:To evaluate the inhaler technique and identify potential errors of patients when treated with inhalers by testing a routinary procedure to be implemented in any community pharmacy.Methods:Adults with asthma/COPD and under inhalation therapy were invited to demonstrate how they use their inhalers. After direct observation it was registered whether all the sequential steps included in the summary of product characteristics (SmPC) were performed.Results:The study involved 67 patients from 4 community pharmacies (Portugal central region): 34 (50.7%) males, 65.4 (SD=18.28) years old, 42 (62.7%) with COPD, and 23 (34.3%) using more than one inhaler. The 67 patients used 95 inhalers, comprising: 57 (60.0%) multiple dose DPI (dry powder inhalers), 18 (18.9%) single dose DPI, 16 (16.8%) pMDI (pressurized metered dose inhalers), 2 (2.1%) pMDI+spacer and 2 (2.1%) SMI (soft mist inhalers). No errors were made only by 9 (13.4%) patients. In the 75 DPIs techniques, the most frequent errors were ‘no previous forced expiration’ (46=61.3%) and ‘no 10s apnea after inhalation’ (51=68.0%); in the 16 pMDIs techniques common errors were ‘lack of hand-lung coordination’ (7=43.8 %), ‘no previous forced exhalation’ (8=50.0%) and ‘no apnea after inhalation’ (10=62.5%). After inhaling from 56 devices containing corticosteroids, 34 (60.7%) of the patients did not wash their mouth.Conclusion:The study demonstrated the possibility of performing this procedure routinely in Portuguese community pharmacies and also its utility, since 58 (87%) of patients had at least one error during the inhalers use.