Tumour necrosis factor (TNF) alpha is involved in the pathogenesis of established lymphoproliferative disease. Serum levels of TNFalpha and its soluble receptors are above normal values in B-cell chronic lymphocytic leukaemia (B-CLL) and they are valuable prognostic markers in lymphoma patients. The production of TNFalpha is genetically controlled. Altered synthesis of TNFalpha has been associated with polymorphisms at the TNF gene cluster (i.e. TNFA, TNFB and LTB). In the present study, we evaluated the prevalence of the known high TNFalpha- and TNFbeta- producing alleles TNF1, TNF2 of the TNFA gene, TNFB1, TNFB2 alleles of the TNFB gene and of the polymorphic alleles TNFd1, d2, d3, d4 and d5 of the microsatellite TNFd in patients with B-CLL, non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD). This study demonstrates that there is no difference in the frequency of the tested TNF alleles between normal controls and cohorts of patients with lymphoproliferative disease. These results indicate that TNF alleles are not genetic predisposing factors in the development of these diseases.