From the stem bark of Erythrina sacleuxii four new isoflavones were isolated and characterized as 5,7-dihydroxy-2',4',5'-trimethoxyisoflavone (trivial name, 7-demethylrobustigenin), 5,7-dihydroxy-4'-methoxy-3'-(3- methylbut-2-enyl)isoflavone [3'-(3-methylbut-2-enyl)biochanin A], 5,7,3'- trihydroxy-4'-methoxy-5'-(3-methylbut-2-enyl)isoflavone [5'-(3-methylbut-2- enyl)pratensein] and 5,7,3'-trihydroxy-4'-methoxy-5'-formylisoflavone (5,- formylpratensein). The structures were determined on the basis of spectroscopic evidence.