OBJECTIVE The primary objective of this study was to describe the single dose pharmacokinetics of ribavirin in subjects with normal liver function and those with various degrees of stable chronic liver disease. Additionally this study assessed the safety and tolerability of ribavirin in this population. METHODS Single oral 600 mg doses of ribavirin were administered to healthy male and female volunteers (n = 6) and patients with stable chronic liver disease (n = 17), in a parallel group study. Pharmacokinetic sampling and tolerability assessments were performed up to 168 h post dose. RESULTS Single oral doses of 600 mg ribavirin were well tolerated by healthy volunteers and patients with varying degrees of hepatic dysfunction. Although mean Cmax increased with the severity of hepatic dysfunction, there was no change in extent of absorption or renal clearance of ribavirin. CONCLUSIONS There are no pharmacokinetic reasons for initial dose adjustment of ribavirin in patients with hepatic dysfunction.