Background: Inhaled therapy has proved to be the most accurate way to control the symptoms of Asthma and COPD. The most commonly delivery system used to control these diseases is the MDI. The primary endpoint of this study is to show the association between an inappropriate inhalatory technique and age. Materials and Methods: This is a cross-sectional study, performed at Centro Médico Naval “Cirujano Mayor Santiago Távara”, in Callao, Peru, in 2014. Patients ≥18 years old that used MDI were included, in our non-probability sampling by convenience. The main variables were age and incorrect practical inhalation technique, according to the guidelines on the correct use of inhalers of the Spanish Society of Pneumology and Thoracic Surgery (SEPAR).The results were analyzed with the Chi² test for bivariate analysis and for multivariate, the Poisson regression with Robust variance. Res...