Thirteen isoquinolinetype alkaloids belonging to five different skeletons have been isolated from Desmos tiebaghiensis. They were identified as the tetrahydroprotoberberines (-)-discretarnine (la) and (-)-stepholidine (lb); the proaporphine (-)-glaziovine (2); the aporphines (-)-laurotetanine (h), (+)-Nmethyllaurotetanine (3b), (+)-boldine (k), (+)-isoboldine (M), (-)-anonaine (k), (-)-asimilobine (4b) and the 7-hydroxy aporphine (- )-norushinsunine (5) ; the morphinandienone (-)-pallidhe (6a) and the benzyltetrahydroisoquinolines (+) reticuline (7a) and (+)-N-methylcoclaurine (7b). This is the first report of a morphinandienone alkaloid in an Annonaceous plant; the biogenetic significance is discussed briefly.