Despite the significant disease burden of bronchiectasis in Korea, there has been no large-scale, representative prospective cohort studies to evaluate clinical characteristics of bronchiectasis patients in Korea. Thus, there has been an urgent need of bronchiectasis cohort study. The Korean Multicenter Bronchiectasis Audit and Research Collaboration (KMBARC) is a prospective, non-interventional observational cohort study of bronchiectasis in Korea. The inclusion criteria are as follows: 1) adult ≥18 years of age with or without respiratory symptoms, 2) bronchiectasis confirmed by chest computed tomography, and 3) stable status at the time of registration. The exclusion criteria are as follow; 1) bronchiectasis due to cystic fibrosis, 2) traction bronchiectasis associated with interstitial lung disease, 3) patients under active treatment against pneumonia, pulmonary tuberculosis, or non-tuberculous mycobacterial pulmonary infection, 4) patients who are unable or unwilling to provide informed consent, and 5) patients who are pregnant. We aim to recruit at least 1,120 patients over the study period more than 26 hospitals in South Korea. Patients will undergo detailed baseline and yearly assessment for up to five years. The study purposes of KMBARC registry are as follows: 1) uncovering the natural course of bronchiectasis, 2) guiding to make an evidence-based bronchiectasis guideline in Korea, and 3) encouragement and facilitation of bronchiectasis studies in Korea. We also expect to perform collaboration studies with other clinical registry, e.g., EMBARC registry to reveal the ethnic differences of bronchiectasis.