A new species and record of Begonia L. from the central highlands is described and illustrated. The new species, B. mangdenensis is assignable to Begonia sect. Platycentrum based on the axillary inflorescence, 4-tepaled staminate flower and 5- tepaled pistillate flower with ovary two locules each with two placentas. B. mangdenensis is most similar to B. lamdongiana, but it is different in its variegated (vs. uniformly green) and velvetly (vs. slightly waxy) upper surface of lamina, villous (vs. glabrous) peduncle, first pair of bracts glabrous (vs. puberulous or hirsute) in abaxial surface, bracts margin entire and ciliate (vs. denticulate or laciniate to biserrate, ciliate). In addition, B. yui Irmsch., previously known from China, is newly recorded from Vietnam.