This paper summarizes the present knowledge of Polyporus s. str. in northeastern China and the Russian Far East. Fifteen species are found in these areas, and a key for the species is given. Statistical variations of spore dimensions are included in the key, and for each species at least 30 spores were measured from the Asian material. A new combination P. fraxineus (Bondartsev & Ljub.) Y.C. Dai, is proposed. The species was earlier known from the type only, but has now been recollected from the Changbaishan Forest Reserve in northeastern China. It is a poorly known species, and seems to be rare. Its emended description is given based on the recent Chinese collections. Type material of P. ulmi was studied, and it turned out to be identical to P. chozeniae. Polyporus chozeniae is considered to 1e a synonym of P. ulmi. Polyporus fraxineus and P. tuberaster are newly recorded from China.