The objective of this study is to evaluate serum levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-a) in a series of patients with hepatitis C virus (HCV)-related mixed cryoglobulinemia (HCV-MC) and to correlate these parameters with the clinical features of the disease. Serum IL-6 and TNF-a were assayed in 61 patients with HCV-MC, in 61 sex- and age-matched patients with HCV chronic hepatitis without cryoglobulinemia (HCV+), and in 61 sex- and age-matched healthy controls. HCV-MC patients showed significantly higher mean IL-6 levels than controls (p=0.005) or HCV+ patients (p = 0.02). Moreover, IL-6 was increased in cryoglobulinemic patients with active vasculitis, even if the statistical significance was not reached (p=0.056). Serum TNF-a levels were significantly higher in HCV-MC than in HCV+ or in controls (p<0.01). The study demonstrates high IL-6 and TNF-a serum levels in HCV-MC patients; moreover, IL-6 levels tended to be higher in HCV-MC patients in presence of active vasculitis.