Trichosporon species are opportunistic pathogens, associated with a high mortality rate in immunocompromised patients. Oligonucleotide primers were used to amplify a 170-bp fragment of small-subunit ribosomal DNA of all species in the genus Trichosporon by PCR. The primers amplify DNAs of all species in the genus Trichosporon, including six causative agents of trichosporonosis. DNAs of other medically important yeasts, such as Candida albicans and Cryptococcus neoformans, are not amplified by this detection system.