GB virus C (GBV-C) infection is common in humans and may persist for decades, although most infected persons clear the virus and subsequently develop antibodies to the envelope glycoprotein. GBV-C replicates in peripheral blood mononuclear cells (PBMCs) and CD4(+) T lymphocytes in vitro, and depletion of CD4(+) T lymphocytes has been proposed as the reason for clearance of GBV-C among persons positive for human immunodeficiency virus. We identified GBV-C RNA in purified CD4(+) and CD8(+) T lymphocytes and CD19(+) B lymphocytes removed ex vivo from infected donors and found that GBV-C replicated in vitro in these PBMC subsets, suggesting that GBV-C is a panlymphotropic virus.