The role of cytotoxicity in the defense mechanisms or pathogenesis of human cutaneous leishmaniasis is not yet well known. In the present work we assessed the presence of NK, CD8+ and CD45RO+ T cells, as well as the expression of a molecule associated with cytotoxic properties (TIA-1) in the lesions of cutaneous leishmaniasis. CD8+ T cells, NK and activated T cells were found within the dermal cell infiltrate. We found a heterogeneous but usually strong expression of TIA-1, a marker of cytotoxic granules of T and NK cells, in human cutaneous leishmaniasis lesions. These data suggest that cytotoxic activity occurs in situ in American cutaneous leishmaniasis and that both NK cells and activated CD8+ T cells are involved in this reaction.