Nasal-type extranodal natural killer (NK)/T-cell lymphoma is an uncommon malignancy. By using a tissue microarray, we characterized 84 cases of extranodal NK/T-cell lymphoma with regard to expression of 18 immunohistochemical markers and the presence of Epstein-Barr virus (EBV) RNA. In our series, CD2 was positive in 69 (93%) of 74 cases, CD3 in 68 (84%) of 81, CD5 in 22 (27%) of 81, CD20 in 0 (0%) of 82, CD29 in 75 (91%) of 82, CD30 in 29 (35%) of 84, CD43 in 81 (96%) of 84, CD54 in 58 (72%) of 81, CD56 in 46 (58%) of 79, CD62L in 23 (28%) of 83, CD183 in 66 (80%) of 83, BCL2 in 33 (39%) of 84, cutaneous lymphocyte antigen in 21 (25%) of 84, granzyme B in 70 (83%) of 84, Ki-67 in 59 (71%) of 83, linker for activation of T cells in 60 (71%) of 84, perforin in 66 (86%) of 77, TIA1 in 76 (90%) of 84, and EBV in 73 (87%) of 84. Hierarchical cluster analysis separated primary cutaneous cases from cases manifesting in other sites based on lower expression of the cell adhesion molecule CD54.