Tyromyces chioneus, commonly known as the white cheese polypore, is a species of polypore fungus. A widely distributed fungus, it has a circumpolar distribution, in temperate boreal pine forests, of Asia, Europe, and North America, causes white rot in dead hardwood trees, especially birch.

Tyromyces is a genus of poroid fungi in the family Polyporaceae. It was circumscribed by mycologist Petter Karsten in 1881. The type species is the widely distributed Tyromyces chioneus, commonly known as the white cheese polypore. The phylogenetic position of Tyromyces within the Polyporales is uncertain, but it appears that it does not belong to the "core polyporoid clade". Tyromyces is polyphyletic as it is currently circumscribed, and has been described as "a dumping place for monomitic white-rot species with thin-walled spores."