Background: Clinical observation has shown that many asthma-affected patients are not familiar with appropriate techniques for inhaler use. This may result in misuse, overuse, or diminished response of the administered therapeutic drugs, or may even result. The purpose of this study is to estimate the inhalation technique and variables associated with misuse of inhalation drugs in clinical practice. Methods: Observational survey was used to evaluate the inhalation technique in 128 outpatients aged 6 months to 64 years. A total of 12 (9.2%) patients were using MDI, 90 (69.2%) in conjunction with spacer; regarding DPI, 21 (16.2%) patients were using the Turbuhaler and five (3.8%) were using the Accuhaler. A trained observer recorded demographic data, asthma symptoms score and patients’ inhalation techniques for each inhaler used against a standardized step-by-step checklist. Results: This study surveyed 128 patients with asthma. The most common noncompliance problem was incorrect use of inhaler devices especially the MDI and Turbuhaler. Of those, only asthmatic patients who received MDI, MDI with spacer, Turbuhaler and Accuhaler used devices correctly 8.3, 22.2, 9.5 and 40%of patients, respectively. No significance difference was found in patient characteristics and using MDI, MDI with spacer and Turbuhaler. There was highly correlation between correct using of Accuhaler and asthma severity. Conclusions: Poor inhalation technique among asthmatic patients is very common, even when they have previously inhalation instruction. Comprehensive inhalation instructions are needed to ensure reliable inhalation technique among patients, and inhalation technique must be checked repeatedly during follow up medical visit