Abstract： Objective To investigate the clinicopathological features and prognosis of natural killer (NK)/T cell lymphoma and to analyze its relationship with Epstein-barr virus (EBV). Methods Totally, 36 cases of cutaneous NK/T cell lymphoma were collected from 2000 to 2010 at the Department of Pathology, Peking University Health Science Center, and classified into primary and secondary groups according to whether there is evidence of extracutaneous involvement within 6 months after diagnosis. Clinicopathological features were analyzed and Epstein-barr virus (EBV) was detected. Results Of these 36 cases, 13 (36.1％) were classified as primary cutaneous NK/T cell lymphoma, 20 (55.6％) as secondary, and 3 (8.3％) remained unclassified because of the lack of clinical data. Males were more likely to develop both primary and secondary cutaneous NK/T cell lymphoma than females, but there was no striking difference in sex ratio between the patients with primary and secondary lymphoma (P ＞ 0.05 ). Compared with the patients with primary cutaneous NK/T cell lymphoma, those with secondary cutaneous NK/T cell lymphoma showed a younger median age at onset (43.5 vs. 54 years, P ＜ 0.05), higher prevalence of B symptoms (including fever, night sweat, body weight loss) and multiple skin lesions (P ＜ 0.05 and 0.01, respectively). EBV was positive in 92.3％ (12/13) of the primary lymphoma cases and 85％ (17/20) of the secondary lymphoma cases. Moreover, the median survival was 8 months in all the cutaneous NK/T cell lymphoma cases, and was significantly shorter in secondary cases than in the primary cases (6 vs. 18 months, x2 = 6.074, P ＜ 0.05). Conclusions Cutaneous NK/T cell lymphoma is an EBV-associated, clinica]ly aggressive disease entity. Patients with primary cutaneous NI/T cell lymphoma seem to have an older age at onset and a better prognosis as compared with those with secondary cutaneous NK/T cell lymphoma.