This was a secondary data analysis study that investigated predictors of successful smoking cessation in Korean using the data from the Fourth Korea National Health and Nutrition Examination Survey (KNHANES VI-3) conducted by Korea Centers for Disease Control and Prevention (KCDC) in 2009. Permission to use the data set was granted by KCDC after reviewing the proposal of this study. The data set was downloaded from the KCDC website (http:// knhanes.cdc.go.kr) free of charge.