Metered-dose inhalers (MDIs) have become a firsthand therapeutic strategy for the management of respiratory diseases, mainly for chronic obstructive pulmonary disease (COPD) and asthma. It has been determined, however, that patients do not always use these devices correctly. Our primary goal was to establish the level of technical knowledge of patients with COPD and/or asthma on the use of MDIs, as well as other associated factors related to the effective use of this delivery method.This study was performed with 191 patients (49.2% male, 50.8% female) diagnosed with COPD and/or asthma at Hospital Universitario Mayor (Bogotá, Colombia). The agreement between different observers on nine aspects of the use of the inhaler was assessed by testing the unweighted kappa correlation coefficient and its significance. The correlations between demographic variables, risk factors, and proper knowledge of the adequate use of inhalers were established by means of the Pearson chi-square test (also called Fisher exact test) (expected values less than 5). Statistical tests were evaluated at a significance level equivalent to 5% (p0.05) in the implementation of the various aspects of the proper use sequence for MDIs. However, there were significant differences related to education levels, socioeconomic status, age, and current occupation. A worse inhaler technique was associated with lower education level (0.034), higher age (p=0.003), and absence of job (p=0.005). Changes in the education of patients on the issue, together with the use of the spacer/valved holding chamber proved to be valid strategies that, with the support of the patients' health-care team, were able to improve the MDI technique of the studied group.