Deficiency of vitamin B(12) and folate is associated with causation of certain precancerous conditions and cancer. The present study was carried out on 56 controls, 167 patients with oral precancerous conditions (OPC) and 214 head and neck cancer patients, to evaluate the plasma vitamin B(12) and folate levels to determine their association with tobacco habits and vegetarianism and several sociodemographic factors. The subjects were interviewed using a health habit and diet questionnaire at the time of blood collection. Simultaneous estimations of plasma vitamin B(12) and folate were done by Dual Count Radioassay. It was found that the habit of tobacco consumption, lower education and low income were among the risk factors. A decrease in the plasma vitamin B(12) and folate levels with respect to tobacco habits, disease progression, and vegetarian diet was also observed. The individuals in the ower quartile for vitamin B(12) and folate were at a higher risk of developing OPC, as compared to those in higher quartiles. Similarly, the patients with OPC in lower quartiles were found to be at a higher risk of developing cancer than their counterparts. There was a significant positive correlation between vitamin B(12) and folate levels in the subjects consuming tobacco, and more so in patients with OPC (r=0.4330, p=0.000). Folate levels were significantly lower in patients with advanced as compared with early disease (ANOVA p=0.006 and Spearman's Rho = -0.211 and p=0.01). The results suggest, potential significance of plasma vitamin B(12) and folate levels in head and neck malignancies which needs to be confirmed by further studies on a large population.