Eight quassinoids, including the antileukemic compound bruceantin, were isolated from Brucea antidysenterica by Kupchan and associates. The authors previously reported two new antileukemic quassinoid glycosides, bruceantinoside-A and -B, from this plant. In this study, two additional new antileukemic isobruceine type quassinoids, bruceanol-A (1) and bruceanol-B (2), were isolated and characterized from the same plant. Bruceanol-A (1) has a molecular formula of C28H30O11, and its structure differs from isobruceine-B in that it has a benzoate side chain at C-15 instead of an acetate group, as confirmed by IR, 1H-NMR, and 13C-NMR comparisons. Bruceanol-B (2) has a molecular formula of C27H36O11, with a hexanoyl side chain at C-15 instead of the acetyl group in isobruceine-B. Both compounds showed significant in vivo antileukemic activity against P-388 lymphocytic leukemia: bruceanol-A exhibited T/C values of 130% (0.5 mg/kg), 129% (1 mg/kg), and 134% (2 mg/kg), while bruceanol-B showed a T/C value of 123% (0.5 mg/kg) (3-day dosing). The control compound 5-fluorouracil had a T/C value of 135% (200 mg/kg, 1-day dosing).