From the basic fraction of the CHCl3 extract of the stem bark of Cananga odorata Hook, F. and Thoms. (Annonaceae), Cave and co-workers reported liriodenine, anonaine, roemerine, ushinine, and canangine, which was later identified as eupolauridine. The present paper reports the isolation and structural elucidation of two alkaloids, one of which is new, from the CHCl3 extract of the stem bark of the parent plant. The powdered stem-bark was extracted first with hexane to remove waxes and then with CHCl3. Examination of the CHCl3 extract by tlc showed two Dragendorff-positive spots, one major and the other minor. The two alkaloids A and B were isolated in pure form using chromatographic techniques. Alkaloid B was identified as the known compound liriodenine. Alkaloid A is new and named sampangine. Its uv spectrum showed a complex pattern characteristic of a highly conjugated system. Acetylation and methylation failed, which indicated the tertiary nature of the nitrogen and the absence of hydroxyl groups; a lack of a bathochromic shift upon addition of base further confirmed the latter. Sampangine showed ir absorption at 1680 cm-1 attributable to a highly conjugated ketone function. The low ratio of hydrogen to carbon suggested the presence of a condensed ring system. The hrms indicated the molecular formula as C15H9N2O. The molecular ion peak at m/z 232 and another strong peak at m/z 204 (M+'-CO) corresponding to the molecular ion of eupolauridine showed sampangine is closely related to eupolauridine but possesses a carbonyl group. The position of the carbonyl group was determined by studying the 1H-nmr spectrum (CDCl3), which showed eight aromatic protons. Coupling constants helped distinguish pyridine ring protons from other aromatic protons. The spectrum established ring D was unsubstituted. On the basis of the spectroscopic evidence, sampangine was assigned the structure 1.