The traditional classification of Gymnopilus (Agaricales) recognizes two primary groups, Annulati and Gymnopilus, based on the presence or absence of a membranous partial veil. While our analyses of DNA sequence data from the nuclear ribosomal ITS1-5.8S-ITS2 (ITS) gene supports the monophyly of the genus, these traditional subgroups were not recovered. Five well-supported clades within the genus were identified through these analyses: 1) the spectabilis-imperialis group; 2) nevadensis-penetrans group; 3) a clade formed by G. underwoodii, G. validipes and G. cf. flavidellus; 4) aeruginosus-luteofolius group; and 5) lepidotus-subearlei group. Relationships among these subgroups were not resolved.