The causative agents of trichosporonosis, Trichosporon cutaneum and its synonyms, were reclassified on the basis of DNA relatedness and the coenzyme Q system. Of the 21 strains, 13 have the Q9 system and could be divided into 5 species with 5 varieties, and 8 have Q10, divided into 4 species. Five intermediate DNA relatedness values were found, as the varietal level, in the Q9 group. Taxonomic relationships among strains showing intermediate values were determined from the results obtained by 2 different methods, the spectrophotometric method and the chemiluminometric method. Based on this study, the following new combinations have been described. These are: Trichosporon loubieri (Morenz) Weijman var. laibachii (Windisch) Shinoda et Sugita, comb. nov., T. asahii Akagi var. faecalis (Batista et Silveira) Shinoda et Sugita, comb. nov., and T. asahii var. coremiformis (Moore) Shinoda et Sugita, comb. nov.