Fomitiporia tenuis sp. nov. and Fomitiporia aethiopica sp. nov. from the Ethiopian highlands are described. Both are characterized by a resupinate habit, globose, dextrinoid basidiospores, cystidioles, and respectively scarcity or absence of hymenial setae. Fomitiporia pseudopunctata and F. robusta are reported also in the same area. The preliminary phylogenetic relationships of F. tenuis, F. aethiopica and F. pseudopunctata are inferred from parsimony analysis based on partial nuclear ribosomal large subunit (nrLSU). A preliminary key to the poroid Hymenochaetales with dextrinoid basidiospores (Fomitiporia, Phellinus s.l., Pseudoinonotus) is proposed.