Objective: To determine the prevalence, location, and distribution of sinus tracts in patients referred for endodontic consultation. Method and Materials: This cohort study included 1,119 subjects referred for endodontic consultation, 108 of whom presented with sinus tracts. Following clinical and radiographic examination, the diameter of the rarifying osteitis lesion on the radiograph was measured and the path and origin of the sinus tracts determined. Signs and symptoms, tooth site, buccal/lingual location, and diameter were recorded. Data were statistically analyzed using Pearson chi-square test. Results: Sinus tracts originated mainly from maxillary teeth (63.1%); only 38.9% originated from mandibular teeth. Chronic periapical abscess was the most prevalent diagnosed origin (71.0%). Broken restorations were highly associated with the presence of sinus tracts (53.0%). The most frequent site of orifices was buccal (82.4%), followed by lingual or palatal (12.0%). Orifices on the lingual aspect of the gingiva were observed in mandibular molars. There was an 86.8% correlation between the occurrence of an apically located sinus tract and apical rarifying osteitis (P .01). Conclusion: Sinus tract in the lingual or palatal aspect of the gingiva is relatively common. Practitioners should look for signs of sinus tract during routine examination. Keywords: location, prevalence, sinus tract, teeth