Begonia duruisseaui Scherber. and B. rahajasoae Scherber., both endemic to the Masoala Peninsula in northeast Madagascar, are described and illustrated. They both belong to Begonia L. sect. Erminea A. DC. The former is related to B. tsimihety Humbert from which it differs by its fewer, larger leaves, with finely denticulate margins and a villous inflorescence. The latter is morphologically related to B. bogneri Ziesenh. and the recently described B. ambodiforahensis Scherber. & Duruiss., although it differs from both by the combination of very narrow leaves with clearly demarcated petioles and blades, which are villous and pilose, respectively.