OBJECTIVE: Dry powder inhalers are a group of inhaled medications commonly used for thetreatment of chronic obstructive pulmonary disease (COPD). Although they can be more easilyadministered than metered dose inhalers, there is a high rate of errors in device use. The presentstudy aims to evaluate the relationship between the ability to learn how to use a Diskus device andcognitive functions in patients with COPD.MATERIALS AND METHODS: The study included 30 inhaler‑näive patients who were newlydiagnosed with COPD. During their first visit, patients were administered a broad array of standardizedneuropsychological tests and given a training on inhaler use. During the second visit, patients weredivided into two groups according to their performance in the use of Diskus device: effective andineffective.RESULTS: Twenty‑nine patients who completed the study showed a negative correlation betweenthe cognitive test scores and Diskus training parameters. The number of errors and duration oftraining increased as the cognitive scores decreased. In Visit 2, a comparison between patientswith ineffective and effective use of the Diskus device showed that cognitive function scores werehigher in those with effective use.CONCLUSIONS: Evaluation of cognitive functions in COPD patients is important in establishing aneffective inhalation treatment.