The isolation and structure determination of three limonoids from Atalantia monophylla (Rutaceae) is described. One of these is the previously reported atalantin and the others, dehydroatalantin and cycloepiatalantin, are structurahy related. These limonoids have been chemically interrelated. Evidence leading to revised structures for atahurtin and dehydroatalantin is presented. The chemical and spectroscopic evidence, including "C NMR, indicate structures 7, 8 and 11, respectively, for the limonoids.