Background: Obstructive airway diseases such as asthma and COPD are defined as a decreased capacity to get air through the conducting airways and out of the lungs. Objective: To study the drug utilization pattern in asthma and chronic obstructive pulmonary disease, determine irrationally (does not comply with prescription) drug usage, and whether they were prescribed following the standard treatment guidelines. Methodology: A total of 150 patients of either sex aged 18 years and above having asthma and/or COPD were included in the study. The medical records of patients were checked and information was recorded. The prescriptions were analyzed for drug utilization patterns. The newly diagnosed patients were followed up and medication adherence was determined after 1 month. Results: Out of all 150 patients there were 103 male and 47 female patients. 54 patients were having asthma, 89 patients COPD, and 7 patients asthma COPD overlap. The majority of the patient were prescribed 1 to 3 drugs per prescription. Inhaled corticosteroids were the highest prescribed drug class. The most commonly prescribed drug combination was budesonide + formoterol. The majority of the patients have poorly adhered to the treatment. Conclusion: Study data highlights that very few drug interactions were identified between prescribed medications. The drugs and their combinations were prescribed according to the standard guidelines GOLD (Global Initiative for Chronic Obstructive Lung Disease) and GINA (Global Initiative for Asthma).