Squamous cell skin cancer is a malignant tumor of epithelial origin, the important role in whose development is played by exposure to ultraviolet radiation, the effect of which is shown through the skin to produce reactive oxygen species that may give rise to characteristic mutations. Restriction fragment length polymorphism analysis was used to reveal the distribution of polymorphic catalase gene variants among healthy individuals and patients with squamous cell skin cancer. Reduced frequency of T/T mutant allele carriers was found among the patients with squamous cell skin cancer, which may point to the role of catalase in the development of this neoplasm.