Nasal and nasal-type natural killer (NK) lymphoma is a distinct clinicopathological entity mostly associated with Epstein-Barr virus. Cases that have widespread lesions are resistant to ordinary anti-cancer therapy and take a highly aggressive course. To date, there are no available data on the relationships between the localization, clinical outcome and expression of adhesion molecules in such cases. We examined the expression of cutaneous lymphocyte antigen (CLA) in 52 cases of NK-cell lymphoma. CLA was highly expressed in cutaneous cases. Also, the CLA+ group (n=29) had a much worse prognosis than the CLA- group (n=23), regardless of the primary site or clinical staging. Univariate analysis identified some significant prognostic factors, and multivariate analysis of these factors showed that the expression of CLA was an independent prognostic indicator. In conclusion, the present findings established that CLA is an independent and important prognostic factor in patients with NK-cell lymphomas.