The worldwide reemergence of tuberculosis is significant. In particular, the incidence of extrapulmonary tuberculosis is increasing. But tuberculous tenosynovitis is rare and may be overlooked as a cause of chronic tenosynovitis. Here, we present a case of a 24 year-old man with a mass lesion on the flexor side of the right wrist. Laboratory findings were generally negative, except for the acceleration of the erythrocyte sedimentation rate, and the tuberculosis skin test was strongly positive. Magnetic resonance imaging (MRI) of the mass lesion of the wrist revealed tenosynovitis. We performed open biopsy and mycobacterial cultures. Thus, we diagnosed the patient with tuberculous tenosynovitis. Tuberculous tenosynovitis is uncommon but should be kept in mind in cases of chronic tenosynovitis.