Chronic hepatitis C virus is a major worldwide cause of hepatitis, cirrhosis, end-stage liver disease, and hepatocellular carcinomas. Combination therapy of ribavirin with short- or long-acting interferon-alpha is now the standard treatment of chronic hepatitis C. This therapy is associated with a wide range of side effects. Although hemolysis is almost an invariable result of ribavirin, black urine due to hemoglobinuria has never been previously reported. We recently encountered two cases of black urine (hemoglobinuria) in patients treated with combination therapy. Based on reports of dark urine in many of our patients, we suggest that this phenomenon may be more common than is currently appreciated. It indicates a marked degree of hemolysis, which prompts immediate measurement of hemoglobin level.