Abstract Background: To investigate the demographic and lifestyles factors associated with vitamin C deficiency and to examine the association between plasma vitamin C level and self-reported physical functional health. Methods: A population-based cross-sectional study using the European Prospective Investigation into Cancer-Norfolk study. Plasma vitamin C level <11 µmol/L indicated vitamin C deficiency. Unconditional logistic regression models assessed the association between vitamin C deficiency and potential risk factors. Associations between quartiles of vitamin C and self-reported functional health measured by Short Form-36 were assessed. Results: After adjustment, vitamin C deficiency was associated with older age, being male, lower physical activity, smoking, more socially deprived area (Townsend index) and a lower educational attainment. Those in the lowest quartile of vitamin C compared to the highest were more likely to score in the lowest decile of physical function [adjusted odd ratio(aOR): 1.43 (95%CI:1.21-1.70)], bodily pain[aOR: 1.29 (95% CI: 1.07-1.56)], general health[aOR: 1.4 (95%CI:1.18-1.66)] and vitality[aOR: 1.23 (95%CI: 1.04-1.45)] SF-36 scores. Conclusions: Simple public health interventions should be aimed at populations with risk factors for vitamin C deficiency. Poor self-reported functional health was associated with lower plasma vitamin C levels, which may reflect symptoms of latent scurvy.