The genetic alterations associated with head and neck cancer (HNC) are numerous and include a variety of different pathways. It has also been shown that numerous tumor suppressor genes are involved in HNC. The LKB1 gene has been defined as a tumor suppressor gene, and somatic mutations of this gene have been identified in many different neoplasms. The aim of this study was to investigate the LKB1 gene in HNC. Nine exons of the LKB1 gene were analyzed by direct sequencing. We detected a novel missense mutation in the nuclear localization signal coding region of the LKB1 gene in 10 tumor samples from patients with HNC. Six different single-nucleotide substitutions were also observed in the introns. In two patients, a 7 bp duplication was detected in intron 3. These results indicate that the LKB1 gene may play a role in the etiology of HNC.