Most of the drugs used to treat obstructive pulmonary diseases are administered by the inhalation route. However, an incorrect inhalation technique may compromise the control of these pathologies. Objectives: The aim of this study was to evaluate the inhalation technique on patients of a community pharmacy and their medication adherence. Methods: A descriptive, cross-sectional observational study was carried out with 59 patients treated with inhalers who were surveyed on their inhalation technique and adherence to treatment. In addition, they were asked for a practical demonstration of their inhalation technique. Results: 47% of the surveyed patients committed critical inhaler use errors despite the fact that 97.3% of them considered they knew how to use properly their devices. The most frequent error was not to wait at least one minute between inhalations when it was necessary to repeat doses. Although 96% of the surveyed patients assured to have received information about how to use the inhaler, only 1% was provided by pharmacists. 47% of the patients showed a good adherence to the treatment. Nevertheless, 60% showed some type of non-compliance, being the erratic non-compliance the most frequent one. Conclusion: This study shows that a high percentage of patients present an incorrect inhalation technique and have a poor therapeutic adherence, which can contribute to a lower effectiveness of the treatment and a worse control of their health problems. A more active role of community pharmacists is needed to prevent this situation.