Chronic draining sinus tracts on the oral mucosa or the skin of the face frequently have dental pathosis. The purpose of this study was to investigate the incidence and the distribution of age, sex, opening, and tooth position of sinus tract cases with dental origin. A total of 678 teeth requiring endodontic treatment and having periapical pathosis at the Department of Conservative Dentistry, Kaohsiung Medical College Hospital, were studied. There were 86 (12.7%) teeth associated with sinus tracts, among these 47 (16.3%, 47/288) were from males and 39 (10.0%, 39/390) were from females. Of the openings of the sinus tracts, 70 were on the facial, 2 were on the palatal, 1 was on the distal, 4 were on the lingual, 2 were on both facial and lingual surfaces of teeth, and 7 were extraorally. The sinus tracts occurred more frequently in the mandibular than maxillary teeth. The maximum number of 34 cases (39.5%, 34/86) were from the 21-30 years of age group. In addition, we also found that the teeth with periapical lesions of larger than 5 mm in diameter are more frequently associated with sinus tracts than those teeth with lesions of smaller than 5 mm in diameter.