Background and Objective: Epidemiologic studies have reported a wide range of prevalence rates for oral lesions across the world. This study aimed to determine the frequency of oral lesions among patients of the Department of Oral Medicine, Shahid Beheshti Dental School, Tehran, Iran in 2014-2015.

Materials and Methods: In this cross-sectional study, forms including demographical information, clinical features of lesions, and medical history were filled out by 2465 patients. Oral lesions were categorized into six groups and were studied clinically and or histopathologically. Anatomic normal variations were not included in the study. Chi-square and Fischer’s exact tests were used to analyze the data.

Results: Out of a total of 2465 patients, 224(9.6%) presented with oral lesions. The frequency of oral lesions among women (122, 51.3%) was statistically higher than men (116, 48.7%) (p= 0.009). White-red lesions (104, 4.22%) were found to be the most frequent group of lesions while geographic tongue (35, 1.42%) was the most common type of lesion. Most oral lesions were found in the age range of 40-60 years. However, no significant difference was found among age groups in terms of presence of oral lesions. Most oral lesions were found in the labial mucosa.

Conclusion: An oral lesion frequency rate of 9.6% was found in our study, with white-red lesions being the most common group and geographic tongue being the most frequent type of lesion. The most common site of oral lesions was the labial mucosa.