Hepatitis C viral (HCV) infection is associated with systemic inflammation and metabolic complications that might predispose patients to atherosclerosis, including cerebrovascular atherosclerosis. The aim of this study was to assess cerebrovascular reactivity in patients with chronic hepatitis C. Seventeen patients with chronic hepatitis C infection, as well as 11 healthy blood donors in the control group, were assessed for cerebrovascular reactivity according to the well-established breath-holding test that uses the transcranial color Doppler for measurement of blood flow velocity. Results obtained during the breath-holding revealed significantly lower average peak systolic (AvPS start, P = 0.018), end-diastolic (AvED start, P = 0.031) and mean velocity values at the very beginning of the breath-holding procedure (AvmeanV start, P = 0.02), as well as a lower mean peak systolic velocity at the end of the breath-holding test (AvPS max, P = 0.02) in the hepatitis C group. Vascular reactivity values, calculated as the breath-holding index, were also significantly lower (P = 0.045) in the hepatitis C group. In conclusion, the results of this study suggest an association between chronic HCV infection and altered cerebrovascular reactivity which may ultimately have an unfavorable effect on cerebrovascular hemodynamics and lead to increased risk of cerebrovascular diseases.