Present study examined various socio-demographic factors, dietary patterns, habit of tobacco consumption andplasma vitamin levels in 56 healthy individuals, 146 patients with oral precancerous conditions (OPC) and 132untreated oral and pharyngeal cancer patients. The subjects were interviewed with a detailed health, habit and dietquestionnaire. Plasma β-carotene, vitamin-A and vitamin-E levels were determined spectrophotometrically. Anincreased incidence of OPC was observed in the age group of <30 years which was associated with tobacco chewing.Whereas, incidence of cancer was in the age group of 30-60 years where habit of tobacco smoking was more prevalent.Majorities of the subjects were from rural area, poor, unaware about association of diet with cancer. The body massindex was lower (p=0.045) in patients with OPC and cancer patients as compared to the controls. Plasma β-caroteneand vitamin-E levels were lower in patients with OPC (p=0.000 and 0.031, respectively) and untreated cancer patients(p=0.000 and 0.071, respectively) than the controls. ROC curve revealed that plasma vitamin levels have ability todiscriminate between controls and cancer patients. Lower plasma β-carotene and vitamin-E levels were observed intobacco consumers as compared to non-consumers. Odds ratio revealed that controls and patients with OPC havingtobacco habit and lower plasma levels of β-carotene were at a higher risk (p<0.05) of developing cancer. Regressionstudy and Analysis of Variance revealed that plasma β-carotene levels were inversely associated (r2=0.14, p=0.001and F=0.000, respectively) with increase in the stage of cancer. The data provide interesting clues of potential role ofdiet, tobacco habits, socio-demographic status and plasma vitamin levels in etiology of oral and pharyngeal cancerin Gujarat, where no such findings are reported.