Peripheral T cell lymphoma not otherwise specified (PTCL-N) and ALK-negative anaplastic large cell lymphoma (ALCL) are heterogeneous categories with poor diagnostic reproducibility. To clarify the biologic features of these categories, we investigated the expression of two chemokine receptors, type 1 (Th1/Tc1)-associated CXCR3 and type 2 (Th2/Tc2)-associated CCR4 in 110 PTCL-N and 35 ALK-negative ALCL cases, as well as the expression of cytotoxic molecules (CM). CXCR3 and CCR4 were expressed in 69 (63%) and 37 (34%) of PTCL-N, and in 12 (34%) and 6 (17%) of ALK-negative ALCL, respectively. In PTCL-N, type 1 pattern (CXCR3(+)CCR4(-)) was dominant (52%), whereas in ALK-negative ALCL, 54% were negative for both (P < 0.0001). CM was expressed in 38% of PTCL-N and 51% of ALK-negative ALCL. CM-positive PTCL-N consisted mostly of type 1 disease, which shows type 1 phenotype. In contrast, type 2 pattern (CXCR3(-)CCR4(+)) was recognized in the CM-negative group only. Among type 1 disease, CM-positive cases had a higher female ratio and more aggressive clinical features than CM-negative cases and a poorer prognosis (P = 0.006). Multivariate analysis confirmed that the type 1 phenotype with CM expression was an independent prognostic factor. In both PTCL-N and ALK-negative ALCL, CM-positive type 1 disease had an extremely poor prognosis.