From the roots of Astragalus kahiricus DC., three known saponins, namely, astraversianin VI, astraversianin X, astragaloside VIII, and a new saponin were isolated and identified by spectral data. The structure of the latter was elucidated by spectral means and assigned as cycloastragenol 3- O-[ beta- D-(2',3'-diacetyl, 4'- trans-2-butenoyl)-xylopyranosyl], 6- O- beta- D-xylopyranoside (kahiricoside I). From the aerial parts of A. hamosus L., the known compounds azukisaponin V and peregrinoside I were isolated. As judged by in vitro tests, the saponins isolated from Astragalus spp. endemic to Egypt were not cytotoxic against a variety of human cancer cells. However, dose-related modulation of lymphocyte proliferation was observed, and structure-activity relationships are described.