Carcinomyces polyporinus is a species of fungus in the class Tremellomycetes.

It is a parasite, growing in the hymenia of various poroid fungi, particularly species of Postia.

[1] Microscopically, it resembles a species of Tremella, but DNA research indicates that it belongs in a different family, the Carcinomycetaceae.

[2] It was first described by British mycologist Derek Reid from Scotland.

[3] It has also been recorded in continental Europe and North America.