Purpose: The aim of this study was to investigate drug prescription patterns for the treatment of asthma and chronic obstructive pulmonary disease (COPD) patients in Korea. Methods: Ambulatory adult patients who were diagnosed and received treatment for the asthma (ICD-10 code J45) or COPD (ICD-10 code J44) from January 2009 to September 2011 in two independent secondary hospitals in Korea were enrolled in this study. Prescribed drug lists were generated based on the evidence-based guidelines and prescribed drug dosage forms were identified from the patient medical records and computerized drug prescription databases of the study centers. Results: Total numbers of asthma and COPD patient enrolled in this study were 2,432 and 2,615, respectively. Individual prescription-based accumulated numbers of patient were 12,021 for asthma and 16,584 for COPD. The most commonly prescribed three drugs were oral predisolone, oral formoterol and oral montelukast for asthma and oral formoterol, oral doxofylline and inhaled tiotropium for COPD. Frequencies of oral drugs were 83.4% and 63.3% while inhalers were 16.4% and 30.2%, for asthma and COPD, respectively. Conclusion: The oral treatment was prescribed more in asthma and COPD patients than inhalers. To enhance the compliance of evidence-based guidelines for these chronic airway diseases, more realistic and specific strategies to increase the use of inhalers recommended as primary treatment options for asthma and COPD would be required.