Phaeostemma surinamensis Morillo & Krings, sp. nov., anew species of Apocynaceae (Asclepiadoideae, Gonolobinae) is described and illustrated, and the new combination Phaeostemma fucata (Woodson) Morillo & Krings, comb. nov., is made. The new species, known only from a lowland wet forest of Suriname, seems to be closely related to Phaeostemma fucata, which is an endemic to Ptari-tepui, a sandstone mountain in the southeastern edge of the Venezuelan Guayana.