We report a clinicomycologic study of eight culture-proven cases (diagnosed from May 1991 to June 1992) of Trichophyton tonsurans (T. tonsurans) infection in Tainan. T. tonsurans is the most common cause of tinea capitis in the United States and Mexico; Trichophyton violaceum (T. violaceum) is the most common cause in South Africa, India, Jordan and the Far East. To date, there has been no written report of infection caused by T. tonsurans in Taiwan. We report six cases of tinea capitis and two cases of tinea corporis which were proven to be T. tonsurans infection. In this small series, as in our previous series on T. violaceum infection, a predominance of adults of the female gender was noted. The median age of the adults was 58 years. The only child patient was an eight-year-old girl with tinea capitis whose mother was also infected. We have observed T. tonsurans infection with an increasing frequency over the last two years in Tainan. In the future, one would expect an increased incidence of T. tonsurans infections in other parts of the country, especially in adjoining cities. Dermatologists should be increasingly alerted to the possibilities of T. tonsurans as an etiologic agent in fungal infection.