The pathogenesis of lichen sclerosus remains unknown. However, it has been frequently associated clinically with autoimmunity. The MHC haplotype A1, B8, DR3 is associated with many autoimmune conditions and has also been associated with the uncommon allele of the tumour necrosis factor (TNF-alpha) promoter polymorphism. This allele is also associated with higher production of TNF in vivo and in vitro, and thus it has been speculated that it is the TNF-alpha gene which underlies the genetic association of many diseases with the autoimmune haplotype. There have been many reports of HLA associations with lichen scleroses, but these have not been concordant. We therefore decided to analyse the TNF-alpha polymorphism in patients with lichen scleroses to determine if TNF-alpha was likely to play a role in susceptibility or severity of lichen scleroses. No association between alleles of the TNF-alpha polymorphism and lichen scleroses was found.