The purpose of the study was to assess relationship between smoking-related questionnaire and urinary cotinine. Seventy-five students of each one class of the first and second grade in one vocational school were administered the smoking-related items of the Youth Risk Behavior Survey October 2000, after which urine samples were collected. Urinary cotinine was detected by qualitative AccuSign Nicotine immunoassay. Positivity of urinary cotinine was detected in 29 of 75 students (38.7%). Kappa coefficients between self-reported smoking behaviors and positivity of urinary cotinine were all statistically significant, showing 0.41, 0.50, 0.28, 0.71 in lifetime smokers, regular smokers, current smokers, and current frequent smokers, respectively. These results showed that self-reported questionnaire may be useful in smoking-related survey and qualitative urinary cotinine may be used as validation of self-reported questionnaire.