Peripheral blood mononuclear cells (PBMCs) from 27 hepatitis C virus (HCV)-infected patients were analysed for the presence of HCV negative strand RNA with strand-specific Tth-based RT-PCR. No negative strand RNA was detected in any sample, and positive strand HCV sequences amplified from PBMCs were identical to those found in serum. These findings suggest that HCV does not replicate in PBMCs, and the presence of HCV sequences at this site is compatible with passive virus adsorption and/or contamination by circulating virus.