Objective: To validate the self-reported smoking status of Korean university students. Methods: Subjects included 322 Korean university in Korea, who participated in an annual health screening. Data on smoking were collected through a self-reported questionnaire and urine test. The data were analyzed by the McNemar test. Results: In the consistency test for males, the results from the questionnaire and the urine test were in agreement, but for females, there was a significant difference between the results reported by the 2 tests (P = 0.001). Conclusions: The findings showed that Korean female university students considerably underreported their smoking behavior.