UNLABELLED Hepatitis C virus (HCV) has cytopathogenic effect not only on hepatocytes, however on salivary glands, monocytes of peripheral blood and lymphoid cells, may explain the systemic manifestations of the infection. HCV activates B and T-cells, modifies the immune response, causes lymphoproliferation, leading the development of B-cell non-Hodgkin's lymphoma (NHL). In the majority of B-cell NHLs immunoglobulin heavy chain (IgH) and light chain (IgL) genes are rearranged and expressed on cell surface in the early stage of the ontogenesis. The analyses of IgH rearrangement prove the clonality of lymphoproliferative disorders giving a powerful approach to the B-cell origin identification of cell proliferation. PATIENTS AND METHODS IgH gene rearrangements were examined from the sera of 57 chronic HCV infected patients and 11 HCV-positive cryoglobulinemic patients as well. RESULTS Cryoglobulinemia was detected in 20% of all chronic hepatitis C virus infected patients and IgH rearrangement was observed in 10.29% (7/68), 4/7 patients (57.14%) suffered from cryoglobulinemia. CONCLUSIONS These results support the hypothesis that IgH gene rearrangement in HCV positive patients can indicate the lymphoproliferative disorder in the HCV infection released B-cell proliferation and lymphoma development.