BACKGROUND: The proper use of inhaler drugs is critical in the management of chronic asthma. In this study, we investigated the inhalation performance of asthmatic patients and effectiveness of the regular education of inhalation technique. METHODS: The 145 asthmatic patients who had been educated the inhaler technique for more than 3 times were enrolled. The inhalation performance of each patient was scored using a checklist form (9 items for metered dose inhaler [MDI], 4 items for dry powder inhaler [DPI]) whenever they visited the clinic. Clinical characteristics affecting inhalation performance were evaluated in the groups using each type of inhaler. RESULT: In MDI, the mean initial performance score was significantly low when the patients were female sex, aged patients (>65 years old), or had lower educational backgrounds. Some items of the checklist, which include tilting head back, placing the mouthpiece with a distance from lips, continuing deep inspiration, and holding breath after inhalation for 10 seconds, were improperly performed in about 25% of the MDI users. No significant change was observed in the final performance scores assessed after intensive repeated education for proper inhalation technique of MDI. In DPI, the mean initial performance score was significantly low in the patients with old age (>65 years old) or lower educational backgrounds. The final performance scores were significantly improved after the repeated education for proper use of DPI inhalation in contrast to MDI. CONCLUSION: For the effective management of asthma, it may be important to choose proper type of inhaler with consideration of individual characteristics of the patients. The evaluation of inhalation performance and regular education of inhalation technique could be useful to maintain and improve the effective use of inhaler, especially in DPI.