Chronic obstructive lung diseases like asthma and chronic obstructive pulmonary disease (COPD) are accompanied by a major burden of symptoms, health care utilization, loss of productivity and cost of medications on the individual and society. India has approximately 15 to 20 million asthmatics patient. Rough estimates indicate a prevalence of between 10% and 15% in children in the age range of five to eleven years. In India, about 3% of all death in 1990 was due to COPD and it getsraised to 6.5% deaths in 2020. Inhalation therapy is a cornerstone of treatment for Asthma and COPD. Delivery of the drugs directly into the airways is the major advantage of inhalation therapy as it results in achieving higher concentrations locally with significantly less risk of systemic side effects. Improper inhaler technique results in reduction in drug concentration in body and getting weak to symptom control.Adherence to regimen in asthma and COPD is important for getting appropriate clinical outcomes and non adherence results in a significant health and economic burden. Adherence may get improved by using simple and easy regimens, teaching patient about self-management, communication, and counseling. Important challenge of adherence is providing a device for measuring the level of it and its acceptance. Current study as a prospective observational study was conducted in the Pulmonology Department of Bangalore tertiary care hospital; aimed to assess the frequency of errors during using inhalers and association between type of devices and patient preferences.