Purpose: This study was conducted in order to evaluate how chemiluminescent lighting($ViziLite^{(R)}$) could increase the sharpness of margin and contrast to normal mucosa in the diagnosis of oral lichen planus(OLP), the most frequent oral premalignant lesion, compared with direct visual inspection under incandescent light. Methods: 41 consecutive patients, diagnosed to have OLP with visual inspection under incandescent light, were further examined with chemiluminescent light. The degrees of margin sharpness and lesion contrast were ranked on a scale from 1 to 3 for all patients under visual inspection and chemiluminescent light. The presence of additional lesion only detected by chemiluminescent light, complication, and discomfort were checked for each patient. After both screening tests, biopsy specimens were harvested from all patients with scalpels and histopathologic assessments were done. Results: All 41 patients were diagnosed to have OLP by both visual inspection and chemiluminescent light examination. This result was definitively diagnosed by histopathology. Degrees of margin sharpness and lesion contrast were increased by chemiluminescent light compared with visual inspection, but only the difference of lesion contrast was statistically significant. In 22.0% of patients, additional lesions were detected and 88.9% of them were diagnosed to have OLP histopathologically. 17.1% of patients noted discomfort and 9.8% of patients showed complications after chemiluminescent test. Conclusion: Chemiluminescent light may not be proper for the screen test of oral cancer or premalignant lesion but showed some possibility for additional diagnostic tool for definitively diagnosed patients in determination of lesion margin and scope.