Cytotoxic lymphocytes are critical in the control of HIV replication, it has been shown that perforin is the key effector of killing machinery for CTLs and NK cells, so we investigated the circulating levels of perforin in CD8+ T cells and NK cells by flow cytometry intracellular stain in Chinese HIV infected individuals, its association with disease progression was analyzed. Our results showed that NK cells express perforin more efficiently than CD8+ T cells, CD8+ T cells expressed perforin higher than that of healthy controls, but NK cells expressed lower perforin than that of healthy controls, both were not correlated with disease progression. but significantly associated with their numbers, anti-retrovirus therapy had no evident effects on peforin expression in CD8+ T cells, but enhanced perfrin expression in NK cells, perforin expression in CD8+ T cells and CD16+ NK cells correlate with CD4+ T cell counts significantly in HAART-treated group. Therefore, different mechanisms may be involved in regulating peripheral perforin expression in different cell types.