['Chronic HCV infection is associated with extra-hepatic manifestations. Recent studies have suggested an immunomodulatory role for vitamin D during HCV infection. We investigated the association between serum vitamin D status and the presence of HCV extra-hepatic manifestations.', '25(OH)D serum levels were assessed in 94 HCV(+)RNA(+) patients [including 48 patients with mixed cryoglobulinaemia (MC) vasculitis]. Correlations between serum 25(OH)D levels and the presence of extra-hepatic manifestations of HCV infection were analysed.', 'Overall, 84 of 94 patients (89%) had hypovitaminosis D (≤30 ng/ml). Patients with vitamin D deficiency vs insufficiency vs sufficiency more frequently had systemic vasculitis (P = 0.02), in particular purpura (P = 0.006), detectable MC (P = 0.008) and low C4 serum levels (P = 0.006). Serum levels of 25(OH)D were also correlated with cryoglobulin and C4 levels and with marginal zone B cells and regulatory T cells. In multivariate analysis, the presence of MC and systemic vasculitis remained independently associated with low 25(OH)D levels.'] Do low 25-hydroxyvitamin D serum levels correlate with the presence of extra-hepatic manifestations in chronic hepatitis C virus infection?