Purpose: A diverse range of measurement methods to evaluate the effect of smoking is more powerful than using a single measure. The objectives of this study were to examine the relationships among smoking pack year, self-reported smoking dependence, and urinary cotinine levels, and to investigate the psychological variables in working men. Method: In this cross-sectional study, we surveyed men working in an electronic company who participated in a smoking cessation program. Among 57 men who completed questionnaires, 25 participate in a test for cotinine levels. Results: Smoking pack year was significantly and positively correlated with the FTND-K (Korean version of Fagerstrom test for nicotine dependence) sum scores (r=0.631, p=0.000) and with the levels of urine cotinine (r=0.463, p=0.023). The relationship between FTND-K sum scores and urinary cotinine levels was also significantly positive (r=0.639, p=0.001). Those with higher social support, especially family support, tended to perceive a higher self-efficacy to smoking cessation. Conclusion: These findings suggest that self-reported smoking pack year and nicotine dependence in working men may be a valid way to evaluate the effect of smoking. A supportive family may influence smoking cessation in working men as it increases self-efficacy to avoid smoking.