Abstract: Two new cytotoxic annonaceous acetogenins, named uvarigrin(1) and uvarigrandin A(3), were obtained from the roots of Uvaria grandiflora Roxb(Annonaceae). Based on X-ray analysis and Mosher's methodology, the overall absolute configuration of 1 was established as 15S,17R,18R,21R,22R,36S.The absolute configuration of 3 was also resolved by Mosher'smethodology. The relative configuration of the previously reported uvarigranin(2) was revised. Compound 1 showed cytotoxicity against HCT-8, Bel₇₄₀₂ and A₂₇₈₀ human tumor cell lines at ED₅₀ levels of 0.15, 0.21 and 0.41μg·ml^-1, respectively.