The novel tryptamine-iridoid alkaloid lagamboside was isolated from the methanolic leaf extracts of Palicourea acuminata (Benth.) Borhidi (=Psychotria acuminata Benth.) collected in Costa Rica. Its structure was determined by extensive NMR experiments and is characterized by an unusual N-glycosylation and an iridoid moiety closely related to the less common vallesiachotamine. The co-occurrence with the rare bahienoside, containing two iridoid moieties, is of chemotaxonomic interest.