BACKGROUND Inhalation therapy has proven to be the best way to control the asthma and chronic obstructive pulmonary disease symptoms. The most commonly used delivery system to control these symptoms is the metered-dose inhaler. The primary goal of this study is to demonstrate an association between incorrect inhaler use and patient age. METHODS This is a cross-sectional study, performed at Centro Médico Naval “Cirujano Mayor Santiago Távara”, in Callao, Peru, in 2014. Patients older than 18 years that used metered-dose inhalers were included. We used film recordings of patients using a metered-dose inhaler and compared their technique with the recommendations on the guidelines on the correct use of inhalers of the Spanish Society of Pneumology and Thoracic Surgery (SEPAR). The main variables measured were age and incorrect inhaler use. The results were analyzed with the Chi squared...