The aim of the study was to evaluate the prevalence of oral mucosal lesions (OML) in adult patients reporting to the dental outpatient department at the Institute of Dental Studies and Technologies, Modinagar, Uttar Pradesh, India. The purpose was to determine the priorities in oral health education, preventive measures, and identify the group in urgent need of treatment.Materials and Methods:The study was conducted over a period of 6 months in 2010, when 8866 subjects were offered structured interviews and standardized extraoral and intraoral examinations according to the World Health Organization (WHO) guidelines.Result:Overall prevalence of OML was 1736 (16.8%), the most prevalent being smoker's palate (10.44%) followed by leukoplakia (2.83%), oral submucous fibrosis (1.97%), oral candidiasis (1.61%), recurrent aphthous stomatitis (1.53%), oral lichen planus (0.8%) and others (0.78%). The highest prevalence of the tobacco habit in both forms was recorded in the group aged 40–44 yearsand those aged between 60 and 64 years who wore dentures. Lesions were most prevalent in those aged 40–44 years with a significant predominance of males at 3:1 (M = 12.6% and F = 4.3%). Patients who consumed tobacco in any form or wore dentures had a significantly higher prevalence of OML (P < 0.001). The highest number of lesions were on the palate (59.7%) followed by buccal mucosa (19.9%). Various normal mucosal variants were recorded. Fordyce's granules (0.13%), fissured tongue (3.3%), leukoedema (1.47%), and lingual varices (2.73%) were also recorded. The tongue showed the highest number of variants (64.4%). Patients were grouped according to the treatment needed under the WHO criteria. One hundred and ninety-seven patients were given oral hygiene instructions only, whereas 1422 patients were advised on change of habit and a follow-up and 674 patients needed definitive treatment.Conclusion:This study thus highlights diagnostic criteria, multifactorial risk factors to make standard measurements of OML a basis for planning and evaluating oral health programs for data collection.