Thirteen new alkaloids have been obtained from the seeds of Aspidosperma oblongum: 10-methoxy-17-epi alloyohimbine (29), 19,20-dehydro-β-yohimbine (30), 3,4-dehydro-β-yohimbine (31), β-yohimbine oxindole (32), β-yohimbine pseudoindoxyle (33), β-yohimbine N-oxide (34), 10-methoxy-β-yohimbine (35), 10-methoxy-α-yohimbine (36), 19,20-dehydro-α-yohimbine (37), aricine pseudoindoxyle (38), methoxy antirhine (39), 10-methoxy sitsirikine (40), 3,4,5,6-tetradehydro-sitsirikine (41). Twenty-two other known alkaloids were also isolated: eight of them have been obtained for the first time from the genus Aspidosperma.