Abstract Background: Barrett’s esophagus is a premalignant condition. It has been reported that several methods of endoscopic ablation in combination with acid suppression result in replacement of specialized columnar epithelium by squamous epithelium. The aim of this study was to assess whether ablation of Barrett’s mucosa by means of heat probe and acid suppression restores normal esophageal mucosa. Methods: Thirteen patients with Barrett’s epithelium but not dysplasia were enrolled in the study. Helicobacter pylori was eradicated when discovered. Thermal energy was applied using a heat probe (pulses of 5 to 10 joules). Four-quadrant biopsies were obtained at 1 to 2 cm intervals 1 to 3 months after the last treatment session. All patients continuously took omeprazole, 40 mg/day. Results: Macroscopically, ablation of Barrett’s mucosa was achieved in all patients after 1 to 5 sessions. Three of the 13 patients had residual specialized columnar epithelium beneath the restored mucosa but not overexpression of p53 and c-erbB-2. During follow-up (6 to 36 months) two patients in whom the length of Barrett’s mucosa was greater than 2.5 cm relapsed after omeprazole discontinuation, whereas another two with length of less than 2.5 cm did not. One patient with residual Barrett’s islands developed low-grade dysplasia. Conclusions: Heat probe is an effective and inexpensive method for Barrett’s ablation. Islands of residual specialized columnar epithelium were found in 23% of patients. The length of Barrett’s epithelium determines relapse after omeprazole discontinuation. (Gastrointest Endosc 1999;50:165-72).