Abstract: Objective: To discuss mutations of p53 and β-catenin genes in nasal type NK/T cell lymphoma. Methods : Gene mutations of p53 (exons 4 through 8) and P-catenin (exon 3) in 20 cases of nasal type NK/T cell lymphoma were analyzed by polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) and then by direct sequencing. Results : p53 gene mutations were found in 8 of 20 cases (40.0%). The majority was missense mutations and G:C to A:T transition was predominant. The frequency of the β-catenin gene was 6 of 20 cases (30.0%), the mutations were all missense mutations. Conclusions : p53 gene mutations might be one of the biological mechanisms of nasal type NK/T cell lymphoma development, but no obvious mutation hot spots. The predominant mutational pattern of p53 and β-catenin gene in nasal type NK/T cell lymphoma was missense mutation.