UNLABELLED The human OGG1 (hOGG1) gene encodes a DNA glycosylase involved in the excision repair of 8-hydroxy-2'-deoxyguanine (8-OH-dG) from oxidatively-damaged DNA. Ser326Cys polymorphism in the hOGG1 gene is involved in the repair of 8-hydroxyguanine in oxidatively damaged DNA, and appears to be related to susceptibility to certain smoking and alcohol-related orolaryngeal cancers. OBJECTIVE To analyse if hOGG1 Ser326Cys (exon 7: m6) polymorphism is associated with tumour localization, T, stage and histologic differentiation, and if radiotherapy results were influenced by this polymorphism. MATERIAL AND METHOD Blood samples were obtained before treatment from seventy one patients with laryngeal cancer and screened by a PCR-RFLP method. RESULTS Although hOGG1 gene is important in DNA repair mechanisms, no significant association was observed between hOGG1 Ser326Cys (exon 7: m6) polymorphism, tumour characteristics and radiotherapy results. CONCLUSION So the analysis of this polymorphism is not important for treatment decision in laryngeal cancer patients.