Graves' disease (GD) is an autoimmune disease, which develops on the basis of an interaction between genetic, environmental and endogenous factors. GD is associated with some HLA genes. Closely linked with them are TNF genes (TNF and LTalpha). Their role in the pathogenesis of GD is still unclear. Two functional polymorphisms within TNF genes include a substitution of G with A in intron I of LTalpha gene and the same one at position -308 in the TNF gene promoter. We carried out a case-control study for the analysis of the contribution of TNF genes to GD in Polish patients. 156 patients with GD diagnosed by clinical data were investigated and compared to 80 healthy persons with negative familial anamnesis. Both TNF and LTalpha were analysed by PCR/Nco I RFLP. The allelic frequency of the rarer TNF2 (A) allele, was 24.7% in GD patients, significantly higher than in healthy persons (9.3%; p<0.0001). The OR was 4.38 for this allele. The frequency of heterozygotes was 41.8% in GD, as compared to 13.6% in the control group. The allelic frequency of the rarer LTB*1 (G) allele was also significantly increased: from 21.9% in the control group to 37.2% in GD patients (p<0.01; OR 2.81). The frequency of heterozygotes was 48.7% in GD, and 28.8% in the control group. The results indicate that TNF genes may contribute to GD in the Polish population.