Objective: Chronic bronchitis (CB) is reported to constitutes 14%-74% of COPD patients, depending on different study design and definitions of CB. The goal of this study is to identify the difference of three definitions for CB made by classic method, Saint Georges Respiratory Questionnaire (SGRQ) and CAT score. Methods: In this study, we extracted data from the multicenter KOCOSS cohort, recruited from 47 medical centers in South Korea since April 2012. We classified patients with 3 different definitions of CB: 1) classic definition 2) SGRQ (using questions regarding cough and sputum), and 3) CAT score (using CAT1 and CAT2). Results: Total of 2,423 patients were enrolled in this study. The proportion of CB was 10.6%, 35.8% and 23.0% by classic, SGRQ and CAT definition. By three definitions, there were consistently significant difference of CB and non-CB patients in smoking history, BMI, mMRC, CAT score, SGRQ score, FEV1 and DLCO. Sensitivity and specificity of SGRQ definition compared to classic definition was 86.2% and 70.1%, and CAT definition was 64.0% and 81.8%. PPV and NPV of SGRQ definition was 25.4% and 97.7%, and CAT definition was 29.4% and 95.1%. Agreement Kappa coefficient between classic definition and SGRQ definition was 0.27, classic definition and CAT definition was 0.30, and SGRQ definition and CAT definition was 0.42. Conclusions: In this study, CB patients in new CB definition regarding SGRQ or CAT score shows similar clinical characteristics compared to classic definition. New CB definitions may be used as an alternative method of classic definition.