Oral submucous fibrosis (OSMF) is a chronic disease of insidious onset sometimes preceded by vesicle formation or stomatitis and always associated with juxta-epithelial inflammatory reaction and fibroelastic changes of lamina propria with epithelial atrophy. This study was planned to know the prevalence and clinical profile of OSMF. Methodology: A hospital based study was conducted on a total of 122 (n 22) OSMF cases who visited the Department Of Oral Medicine and Radiology, Tamil Nadu Government Dental College and Hospital, Chennai, during the period of May 2015 and October 2015 (6 months). These cases were retrospectively analysed based on the patients' data available in the department. Information such as age, sex, demographic data, socioeconomic status, habits and their duration, symptoms like burning sensation, dysphagia, and clinical signs such as difficulty in mouth opening, tongue protrusion, assessment of clinical staging and grading based on Lai DR classification (1995) of maximum interincisal distance (Group A - >35mm, Group B – 30-35mm, Group C -20-30mm, Group D - 20 mm) along with drug administered and their responses were analysed and the results obtained. Result: The total number of cases included in the study was 122. There were 105 males and 17 female patients, thus giving a predominance of male over female. The majority of our patients were in the 21 to 40-year age group. Most of them were educated (n 103) and had a middle (n 45) and low (n 77) socioeconomic status, thus indicating chewing habits are more prevalent in the younger age group and educated class. Personal oral habits were present in all patients (n 122); Pan Masala chewing (n 98) contributed to a greater number of OSMF cases followed by tobacco (n 11) and betel nut (n 6) and multiple (n 4) chewing habits. The duration of these habits was up to 5 years (n 93) and greater than 5 years (n 29) in these patients. The majority of our cases reported with symptoms to our institution had habits within the first 5 years. Symptoms such as a burning sensation of oral cavity (n 116) and inability to open the mouth (n 113) was present in most of the OSMF patients. Other symptoms such as inability to protrude the tongue (n 44) and difficulty in swallowing (n 9) were also present. All cases had changes in colour of buccal mucosa and palpable fibrotic bands in the oral cavity. According to Lai Dr (1995) classification5, patients in Group B (n 22), Group C (n 60), and Group D (n 40). The majority of our cases belonged to Group C. Patients in Groups C and D showed increased duration of chewing habit and severe burning sensation and restricted mouth opening. Conclusion: The majority of the patients were in the younger age group with male predominance. Patients with a longer duration of habit showed increased severity of burning sensation and restricted mouth opening affecting their quality of life. Early diagnosis and early intervention can prevent progression of OSMF to malignant transformation. Early intervention of OSMF can be achieved through proper counselling and motivation of patients. OSMF can be easily preventable through appropriate measures such as health education and creating awareness regarding the ill effects of the consumption of tobacco products at a community level. Schlagwörter: Oral submucous fibrosis, trismus, potentially malignant