BACKGROUND: Oral submucous fibrosis (OSMF) is a chronic, progressive, scaring high risk precancerous condition of the oral mucosa seen primarily in the Indian subcontinent and in South East Asia. The exact etiology of OSMF is not well understood. Various factors are being studied such as genetic, autoimmune, nutritional and environmental agents. The increasing use of pan masala/gutkha, a mixture of tobacco and a less moist form of betel quid lacking the betel leaf, is associated with an earlier age of onset of OSMF which may play role in initiation and progress of this condition. AIM AND OBJECTIVES: The aim of this study was to investigate the role of various oral chewing habits in etiology of OSMF and objectives was to investigate the risk of betel quid chewing with or without cigarette smoking, alcohol consumption on OSMF and other mucosal lesions. Also to co – relate the effect of duration and frequency of these habits with severity of the OSMF condition. MATERIALS AND METHODS: The study group comprised of 120 patients of OSMF and 120 age and gender matched patients were taken as control. Study subjects were drawn from the patients attending the outpatient department of Oral Medicine and Radiology, for different complaints and clinically diagnosed cases of OSMF were included. Diagnosis of OSMF was made on basis of history and clinical features of OSMF that includes mucosal blanching, burning sensation, restricted mouth opening and presence of fibrous bands. A predetermined data sheet was used to record the complete history, including various oral habits – the frequency, duration, and type (areca nut, pan masala, betel quid) along with tobacco, smoking and alcohol habits with the clinical findings. After that biopsy was taken from representative site and was sent for histopathological examination for confirmation. Results: The maximum number of cases was in the age range of 21-30 years (35.8%). The mean age in case group was 33.59 ± 11.51yrs. The male to female ratio of OSMF was 6.05:1. It was found that chewing areca nut/quid or pan masala was directly related to OSMF, with the risk being greatest for pan masala, chewed by a comparatively younger age group and was associated with OSMF changes earlier than areca nut/quid chewing. However, chewing or smoking tobacco, alcohol with various other chewing habits did not increase the risk of developing OSMF.