Nasal natural killer/T-cell lymphoma (NNKTL) is associated with Epstein-Barr virus and has a poor prognosis because of local invasion and/or multiple dissemination. Various chemokines play a role in tumor proliferation and invasion, and chemokine receptors including the C-C chemokine receptor 4 (CCR4) are recognized as potential targets for treating hematologic malignancies. The aim of the present study was to determine whether specific chemokines are produced by NNKTL. We compared chemokine expression patterns in culture supernatants of NNKTL cell lines with those of other lymphoma or leukemia cell lines using chemokine protein array and ELISA. Chemokine (C-C motif) ligand (CCL) 17 and CCL22 were highly produced by NNKTL cell lines as compared to the other cell lines. In addition, CCL17 and CCL22 were readily observed in the sera of NNKTL patients. The levels of these chemokines were significantly higher in patients than in healthy controls. Furthermore, we detected the expression of CCR4 (the receptor for CCL17 and CCL22) on the surface of NNKTL cell lines and in tissues of NNKTL patients. Anti-CCR4 monoclonal antibody (mAb) efficiently induced antibody-dependent cellular cytotoxicity mediated by natural killer cells against NNKTL cell lines. Our results suggest that CCL17 and CCL22 may be important factors in the development of NNKTL and open up the possibility of immunotherapy of this lymphoma using anti-CCR4 mAb.