Objective: To learn about the use of various chewing substrates, such as areca nut and gutka, among subjects with oral submucosl fibrosis (OSMF) and controls with no oral mucosal lesions. Materials and Methods: In this hospital-based case-control study, 220 patients with OSMF were selected and compared with matched controls with regard to dietary habits, including spice use, smoking history, and preference for chewing substrates. Relative risk of various chewing habits was calculated using an odds ratio and logistic regression analysis to understand the influence of chewing habits, spices, and smoking on the development of OSMF. Discriminate analysis was employed to determine which risk factors were valid and reliable discriminators between individuals with or without OSMF. Results: The relative risk of developing oral submucosal fibrosis was highest with gutka-chewing habit (relative risk, 1,142.4), which was significant (P .01) at 95% confidence interval. The next highest relative risk for development of oral submucosal fibrosis was observed for the combination of gutka with other chewing habits. The relative risk of developing submucosl fibrosis increased with the frequency of chewing habit up to 15 times daily with a duration of habit up to 4 years. The relative risk decreased with chewing frequency beyond 15 times daily and 4 years in duration. Logistic regression and discriminative analysis show that chewing areca nut and gutka, especially daily, greatly influence the development of submucosl fibrosis. Conclusion: This study suggests that chewing commercially available areca-nut preparations such as gutka is strongly associated with the development of oral submucosl fibrosis. Keywords: areca nut, chewing habit, gutka, relative risk