Abstract We tested the association between tooth loss and oral hygiene and the risk of esophageal squamous cell carcinoma (ESCC) in people living in a high-risk area of Iran. We used a case-control study of pathologically confirmed ESCC cases (n = 283) and controls (n = 560) matched on sex, age, and neighborhood. Subjects with ESCC had significantly more decayed, missing, or filled teeth (DMFT) with a median (interquartile range) of 31 (23-32) compared with controls 28 (16-32; P = 0.0045). Subjects with ESCC were significantly more likely than controls to fail to practice regular oral hygiene (78% versus 58%). In multivariate-adjusted conditional logistic regression models, having 32 DMFT compared with ≤15 conferred an odds ratio (95% confidence interval) of 2.10 (1.19-3.70). Compared with daily tooth brushing, practicing no regular oral hygiene conferred an odds ratio (95% confidence interval) of 2.37 (1.42-3.97). Restricting the analysis to subjects that had never smoked tobacco did not materially alter these results. We found significant associations between two markers of poor oral hygiene, a larger number of DMFT and lack of daily tooth brushing, and risk of ESCC in a population at high risk for ESCC where many cases occur in never smokers. Our results are consistent with several previous analyses in other high-risk populations. (Cancer Epidemiol Biomarkers Prev 2008;17(11):3062–8)