Vervet monkeys were used to characterize immune associated cell types recruited into lesion sites as a result of experimental primary and secondary infections with Leishmania major. A heavy cellular infiltration consisting primarily of CD8+ (cytotoxic/suppressor) T cells were observed in the lesions. A small number of B lymphocytes and NK cells were also stained. Changes in cell type populations observed in the lesions were similarly reflected in the draining lymph nodes. Studies from control sites in all the animals revealed the presence of CD8+ T cells both in the epidermis and dermal layers of the normal skin. B cells, CD16 (NK cells) and CD4 (helper T cells) positive cells were virtually absent in the normal skin. It was concluded that CD8+ T cells were the predominant cells in the lesions. It also appeared that similar cell types were restricting the parasites at the lesion site both in primary and secondary L. major infections in vervet monkeys.