Hyphodontia serpentiformis sp. nov. is described and illustrated. It shows the common micromorphology of Hyphodontia species, i.e. small, suburniform basidia and uniguttate basidiospores. It is close to members of the H. bara-jovis group, but differs in having basally thick-walled basidia and thick-walled conspicuously sinuous hyphal elements in the aculei. Cultural and ultrastructural characters are discussed.