Clinical isolates of Trichosporon cutaneum, the causative agent of trichosporonosis, were identified on the basis of DNA relatedness. Of the 10 strains from deep-seated and mucosa-associated infections, 9 were identified as T. asahii and 1 was identified as T. ovoides. The two superficial strains were identified as T. cutaneum and a variety of T. montevideense. These findings suggest that T. cutaneum is a heterogeneous species in clinical samples and that the causative agents of trichosporonosis exist in four or more species.