To develop novel anti-leukemic medicine, we have prepared a Korean traditional medicine, named Hang-baek-Tang, which is composed of 8 kinds of anti-leukemic medicinal plants. The water extracts was examined anti-leukemic activity using the human leukemia cell line, HL-60 cells. HL-60 cells showed the growth inhibition and several apoptotic features, including DNA ladders, morphological changes, by treatment of the cells with Hang-Daek-Tang. We have observed that Hang-baek-Tang induced the activation of caspase-3, caspase-8 and caspase-9. Further molecular analysis demonstrated that Hang-baek-Tang induced cleavage of PARP and increase of hypodiploid (Sub-G1) population in flow cytometric analysis. These results indicate that Hang-baek-Tang has been considered to exert anti-leukemic activity through the procaspase-3 activation pathway.