A new species of Dioscorea from South Africa, D. strydomiana Wilkin, is described and illustrated. It differs from the related species D. elephantipes (L’Hér.) Engl., D. hemicrypta Burkill and D. sylvatica Eckl. in its tuber surface, leaf morphology, texture and habit, male flower tepal, filament and pistillode size, the length of the stipe between the ovary apex and the torus in female flowers and in capsule shape. Just two populations and c. 200 individuals in total exist, and significant threats have been reported, making D. strydomiana critically endangered. Thus its conservation and sustainable use are discussed.