Spatholobus suberectus belonging the family Leguminosae has been used for promoting blood circulation, removing blood stasis, tonifying the blood, relaxing tendons, stopping internal bleeding and eliminating dampness in oriental traditional medicine. This study investigates whether the water extracts of S. suberectus induce apoptotic cell death in Jurkat T-acute lymphoblastic leukemia (ALL) cells. Jurkat cells were increased inhibitions of cell viability in a concentration-dependent manner by S. suberectus, as measured by cell morphology. The capability of S. suberectus to induce apoptosis was associated with proteolytic cleavage of specific target protein such as poly (ADP­ribose)polymerase protein suggesting the possible involvement of caspases. The purpose of the present study is also to investigate the effect of S. suberectus on cell cycle progression. G1 checkpoin related gene products tested (cyclin D1, cyclin dependent kinase 4, retinoblastoma, E2Fl) were decreased in their protein levels in a dose-dependent manners after treatment of the extract. These results indicate that the increase of apoptotic cell death by S. suberectus may be due to the inhibition of cell cycle progression in wild type p53-lacking Jurkat cells.