Inaccurate use of medication inhalers can reduce effectiveness, patient adherence, and disease stability. Therefore, the accurate use of inhalers in patients with chronic obstructive pulmonary disease (COPD) is crucial. This cross-sectional study evaluated 196 Korean patients with COPD for step-by-step accuracy of inhaler use with four different types of inhalers (metered-dose inhaler [MDI], Turbuhaler, Diskus, and HandiHaler); differences in accuracy levels by sociodemographic or clinical characteristics were evaluated. Descriptive statistics and t tests were used for data analysis. The proportion of patients with completely accurate inhaler use was low, ranging from 21.9% (Turbuhaler) to 46.2% (MDI). Errors with all types of inhalers were most commonly seen in the "breathing out" steps, before and after medication inhalation. Personalized nursing educational programs, correcting errors individually for each patient, could dramatically increase the accuracy of inhaler use and the effectiveness of the inhaled medications in patients with COPD.