Perenniporiopsis gen. nov. is described to accommodate Perenniporiopsis minutissima spec. et comb. nov. Phylogenetic analyses based on two data sets, [ITS n28S nrRNA] and [ITS, n28S, mtSSU, tef1], and using Maximum Parsimony, Maximum Likelihood and Bayesian inferences, showed that specimens of Perenniporia minutissima form a monophyletic well-supported clade within the core polyporoid clade, The new genus grouped with the Abundisporus, Perenniporiella and Perenniporia s.s. lineages, and is phylogenetically distinct from the Perenniporia s.s. lineage (100% BS, 99% MP, 1.00 BPP). Morphologically, the consistency of the basidiocarps, waxy when fresh, drying rigidly osseous, as well as the large basidiospores characterize this species and distinguish it from Perenniporia s.s. The species seems to be endemic to temperate east Asia, and is known from temperate Japan and China.