Background: Traditionally, COPD can be classified as chronic bronchitis or emphysema. However, some patients showed both features of chronic bronchitis and emphysema. Moreover, there are patients who can be classified neither chronic bronchitis or emphysema. Purpose: To examine clinical characteristics of patients with COPD. Methods: Patients were recruited from 49 centres in Korea, as part of the COPD cohort (KOCOSS) study. Results: Total 223 patients with COPD were eligible for analysis. Age was 68.0±7.6 (Mean±SD) and 88.3% were male. FVC, FEV1, and FEV1/FVC were 3.08±0.84 L (83.24±19.00%), 1.42±0.56 L (51.98±17.12%), and 45.88±11.52%. Mean CAT score was 16.27±8.36. Patients were classified as chronic bronchitis (C) or emphysema (E). We analyzed characteristics of patients according to four groups - C(+)E(+), C(+)E(-), C(-)E(+), and C(-),E(-). The percentage of patients were 21.5%, 33.1%, 24.0%, and 21.5 %, respectively. Mean CAT score were 18.35, 11.72, 19.42, and 19.94 (P＜0.01). Mean FEV1/FVC were 39.84%, 48.25%, 42.12%, and 50.01% (P＜0.01). Conclusion: Clinical characteristics were significantly different according chronic bronchitis and emphysema.