The close chromosomal proximity of major histocompatibility complex and tumour necrosis factor genes may suggest the involvement of the latter in the pathogenesis of immunological diseases associated with HLA antigenes. The major histocompatibility complex antigens may play a certain role in the pathogenesis of lichen planus. Therefore we examined the -308 promoter polymorphism of tumour necrosis factor gene in patients with lichen planus. Sixty-six patients and 66 age- and sex-matched controls participated in the study. Genomic DNA from patients and controls was typed for tumour necrosis factor (-308) polymorphism using an allele-specific polymerase chain reaction. We did not find any correlation between genotype distribution, allele frequency and lichen planus. In our study we failed to observe any association between a genotype and mean level of tumour necrosis factor in plasma of our patients.