The purpose of the present study was to evaluate the impact of frozen red cell transfusion on the transmission of hepatitis C virus (HCV) before the introduction of blood donor screening. Anti-HCV antibodies were detected in 59 patients with sickle-cell disease who required chronic transfusions and had exclusively received frozen red blood cells (RBC). The files were reviewed for clinical signs of chronic hepatitis C. Anti-HCV antibodies were detected in 2 adult patients; both also had clinical evidence of HCV infection. No other patient showed signs of acute or chronic HCV hepatitis. In a control group of 28 patients who had received nonfrozen RBC transfusions, the prevalence of anti-HCV antibodies was 25%. So, our study seems to indicate that the use of frozen RBC had reduced the risk of HCV contamination.