Objectives: The purpose of this study was to investigate the relationship between smoking and mental health among Korean by age group. Methods: Hierarchial logistic regression and χ2-test were conducted based on complex sample analysis using statistics from the 6th Korea National Health and Nutrition Examination Survey conducted 2015. The study sample comprised 6,254 aged over eleven years old. Results: The statistically significant difference between smoking and mental health were found. Subjective health status, suicidal ideation and stress perception except for depression were statistically significant by age group. In the final model, the significant factors influencing current smoking were gender, ages, economic status, education level, cohabitation with spouse, subjective health status, suicidal ideation, stress perception and drinking frequency. Conclusions: Factors identified in this study need to be considered in programs directed at prevention of smoking and promotion of mental-health by tailoring to age group as well as policies.