T-cell lymphomas comprise a heterogeneous group of lymphoproliferative disorders that include approximately 10-15% of all lymphomas, and there is a geographic variation in their frequency. With the exception of a few subtypes that are associated with a more indolent course, the majority of T-cell lymphomas are aggressive in nature. Patients with peripheral T-cell lymphomas (PTCL) have an especially poor prognosis, due both to the aggressive disease course as well as the lack of effective treatments. A number of PTCL subtypes have now been defined, although the histologic, immunologic, and cytogenetic distinctions between some subtypes are subtle. Proper diagnosis of the PTCL subtype is important, as each subtype is associated with a varying prognosis and thus may be treated differently. There is no true standard of care for PTCL, and this aggressive disease has historically been treated with therapeutic regimens designed for B-cell lymphomas, such as the cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) regimen. However, studies now show that these regimens are not optimal for most patients with PTCL. Therefore, recent efforts have focused on the development of therapeutic regimens designed to be more effective in PTCL, some of which are specifically targeted against T-cell markers. A number of these agents now show promise in the treatment of both frontline and relapsed/ refractory disease.