To investigate the significance of expressions of p53 and p21 in nasal NK/T-cell lymphoma (NKTL) and their relationship with cell proliferation and apoptosis.Sixty-two cases of NKTL were examined for p53, p21 and Ki67 proteins by means of tissue microarray technique, TUNEL and immunohistochemistry. The proliferation index (PI) was determined by expression of Ki67 proteins.The positive expression rates of p53 and p21 proteins in NKTL were 79.03% and 58.06% respectively. The positive expression rates of p53 in Ann Arbor stage I, II, III and IV NKTL were 69.57%, 75%, 86.67% and 100% respectively, while those of p21 were 47.83%, 56.25%, 60% and 87.50%. With the progression of tumor, the positive expression rates of p53 and p21 proteins gradually increased. And there were significant differences between them (P0.05).The expressions of p53, p21 and Ki67 proteins are closely related with the pathogenesis and progression of NKTL. Combined detection of p53, p21 and Ki67 is a good marker to judge the biological behavior of NKTL, such as the proliferation and the invasiveness of the tumor.