Introduction: Experimental evidence suggests that vitamin D may be protective against tobacco-related cancers through inhibition of the formation of tumors induced by tobacco carcinogens. To our knowledge, only one previous epidemiological study investigated the association between vitamin D status and tobacco-related cancer risk and no study focused on vitamin D-related gene polymorphisms. Objectives: Our objectives were to prospectively study the association between plasma 25-hydroxyvitamin D (25OHD) concentration, vitamin D-related gene polymorphisms and the risk of tobaccorelated cancers. Method / Design: 209 tobacco-related cancers were diagnosed within the SU.VI.MAX cohort (1994-2007), and matched to 418 controls as part of a nested case-control study. Tobacco-related cancers (i.e. cancers for which tobacco is one of the risk factors) included several localizations in the respiratory, digestive, reproductive and urinary systems. Total plasma 25OHD was assessed with Roche Cobas® electrochemoluminescent assay. Polymorphisms were determined with TaqMan assay. Conditional logistic regression models were computed. Results: A 25OHD concentration≥30ng/ml was associated with a reduced risk of tobacco-related cancers (OR≥30vs.<30ng/ml=0.59 (95%CI 0.35-0.99), P=0.046). This association was observed in former or current smokers (OR≥30vs.<30ng/ml=0.43 (0.23-0.84), P=0.01) but not in never smokers (P=0.8). VDR FokI AA genotype and RXR rs7861779 TT genotype were associated with an increased risk of tobacco-related cancers (OR MT vs. WT=1.87 (1.08-3.23), P-trend=0.02 and OR HT+MT vs. WT=1.60 (1.07-2.38), P=0.02 respectively). Conclusions: In this prospective study, high vitamin D status (25OHD≥30ng/ml) was associated with a decreased risk of tobaccorelated cancers, especially in smokers. These results, supported by mechanistic plausibility, suggest that vitamin D may contribute to tobacco-induced cancer prevention in smokers and deserve further investigation