Eight new cycloartane-type triterpenoids, cycloartan-24-ene-1alpha,2alpha,3alpha-triol (1), 3beta-acetoxycycloartan-24-ene-1alpha,2alpha-diol (2), 1alpha-acetoxycycloartan-24-ene-2alpha,3beta-diol (3), 3beta-isovaleroyloxycycloartan-24-ene-1alpha,2alpha-diol (4), cycloartan-24-ene-1alpha,3beta-diol (5), cycloartan-23 E-ene-1alpha,2alpha,3beta,25-tetrol (6), and an epimeric mixture of 24 R,25-epoxycycloartane-1alpha,2alpha,3beta-triol (7) and 24 S,25-epoxycycloartane-1alpha,2alpha,3beta-triol (8), together with one known compound, cycloartan-24-ene-1alpha,2alpha,3beta-triol (9), were isolated from the resinous exudates of Commiphora opobalsamum. Their structures were established on the basis of mass spectrometry and multidimensional NMR spectroscopy. The cytotoxicity of compounds 1-9 was evaluated against the PC3 and DU145 human prostate tumor cell lines. All of the compounds except 1 and 5 exhibited moderate cytotoxicity against PC3 or DU145 cells with IC50 values ranging from 10.1 to 37.2 microM.