Six new triterpene glucosides, cumingianosides A-F (1-6) as well as a trisnor- and a tetranortriterpene glucoside, cumindysosides A (7) and B (8), respectively, with a 14,18-cycloapoeuphane-type skeleton have been isolated from Dysoxylum cumingianum as antileukemic principles. The structures were established on the basis of chemical and spectroscopic evidence. Among them, compounds 1 and 3 exhibited potent selective cytotoxicity against MOLT4 human leukemia cell with ED50 of <0.00626 and <0.0045 μg/mL, respectively. As a result of our continuing search for novel plant antitumor agents active against human tumor cell lines, the MeOH extract of the leaves of Dysoxylum cumingianum (Meliaceae) were found to show significant (ED50 ≤ 20 μg/mL) cytotoxicity in RPMI-7951 and TE-671 tissue culture tumor cells. Subsequent bioassay-guided fractionation with these tumor cell lines in vitro has resulted in the isolation of new triterpene glucosides, cumingianosides A-F (1-6), and a trisnor- and a tetranortriterpene glucoside, cumindysosides A (7) and B (8), respectively, as cytotoxic principles. We report herein on the isolation and characterization of these compounds and their cytotoxic activity.