To evaluate the effectiveness of endoscopic CO₂ laser cauterization (ECLC) as a definitive treatment of congenital pyriform sinus fistula (CPSF). Eleven patients with CPSF underwent ECLC between January 2011 to March 2013 at Guangdong General Hospital. Of the 11 patients aging from 20 to 672 months (median: 60 months), there were 4 males and 7 females; 10 lesions located in the left necks and 1 located in the right; 6 untreated previously and 5 recurrent; 10 sinus (with internal opening) and 1 fistula. The presentations included reduplicative neck swelling, pain, or a fistulous opening with purulent discharge at the anterior neck region. Preoperative examinations included barium esophagogram, CT, MRI and so on. Six patients had at least received one time incision and drainage procedure previously. All patients had been treated with antibiotics in acute infection period. After inflammation subsided, the openings of pyriform sinus fistula were confirmed by esophagoscopy and then ECLC on internal opening was routinely performed.Esophagoscopy was carried out again by 3 months later in every patient, the same technique would be performed immediately if the internal opening was not completely closed. The existence of an orifice in the pyriform fossa was identified by esophagoscopy in 11 patients. In 9 patients, the treatment was successful and the internal opening completely closed after the first ECLC. However, the other 2 patients received the second cauterization 3 months later because of the incomplete close of the internal opening. The average number of treatments was 1.2 times. No complications such as dysphagia, hoarseness occurred with the endoscopic procedure. Both the patients and their families were satisfied with the cervical appearance. All the patients had an uneventful recovery and remained no symptom from 11 to 35 months (median: 24 months). The endoscopic CO₂ laser cauterization is safe, effective, repeatable and minimally invasive, which can be suggested as first-line treatment for congenital pyriform sinus fistula.