Anti-hepatitis C virus (HCV) antibody prevalence was investigated in 228 patients with lymphoproliferative disorders (LPDs). Twenty-six of 228 (11.40%) patients with LPDs were positive for anti-HCV which was higher than the donor population (P = 0.0007). Nine of 98 cases with non-Hodgkin's lymphoma, five of 47 cases with multiple myeloma, seven of 36 cases with Hodgkin's disease, four of 38 cases with chronic lymphocytic leukaemia and one of nine cases with acute lymphoblastic leukaemia had anti-HCV antibody. In all patients, odds ratio (OR) for anti-HCV was 24.09. This value was higher in patients less than 35 years as 62.04 for below 25 years and 32.00 for between 25-35 years. Our findings suggest that HCV infection might be a causative and/or contributing factor in lymphoproliferation.