Twelve new alkaloids have been obtained from the root bark, trunk bark, and leaves of Aspidospenna marrgravzanum: 16-epi isositsirikine 3S,4S N-oxide (%), 3,4,5,6 tetradehydro- 18,19 dihydrocorynantheol (37), 2-ethyl-3[2-(3-acetyIpiperidino) ethyl] indole (H), 18-oxohaplocidine (39), 16(S)isositsirikine N-oxide (40, 18,19-dihydroantirhine (41). isogeissoschizol (42), 10-methoxy-isogeissoschizol (43), isoantirhine (44) 17,4',5 ',6' tetrahydro- 17(R) usambarensine N-oxide (45), Nb-carbomethoxy- 17,4', 5',6' tetrahydro-17(R)usambarensine (%), N,.-carboethoxy- 17,4',5' ,6' tetrahydro- 17(R)usambarensine (47). Thirty-four known alkaloids were also isolated: 16 of them have been obtained for the first time from the genus Aspidosperma.