Cytotoxic lymphomas are peripheral T- and natural killer-cell lymphomas with primary or secondary skin manifestations. They constitute a heterogeneous group of lymphoproliferative disease. They are characterized by expression of cytotoxic proteins and are frequently associated with an aggressive clinical course. A brief introduction to cytotoxic lymphocytes and proteins is followed by a detailed description of clinical, histological, immunohistochemical and genetic characteristics of cutaneous cytotoxic lymphomas.