Background: Specialized intestinal metaplasia (SIM) in Barrett's esophagus (BE) is not identifiable by standard endoscopy. Acetic acid instillation enhances the ability to detect columnar epithelium at the squamocolumnar union. Enhanced magnification endoscopy involves the combined use of magnification endoscopy with acetic acid. This study assessed the value of enhanced magnification endoscopy in detecting SIM in patients with BE. Methods: Patients undergoing endoscopic surveillance because of short segment BE without dysplasia underwent enhanced magnification endoscopy with 1.5% acetic acid instillation. Standard endoscopy was followed by magnification endoscopy and repeated after acetic acid spraying. Surface patterns were characterized prior to and after acetic acid spraying. The observed surface patterns were compared with histology results. Results: Forty-nine patients, 9 women and 39 men, with a mean age of 50.5 years were studied. One was excluded because of unclear definition of the surface pattern. Enhanced magnification endoscopy detected 4 different mucosal surface patterns: I, round pits; II, reticular; III, villous; and IV, ridged. A total of 129 areas were examined. Standard endoscopy identified an endoscopic pattern in 1.5% of the areas, standard endoscopy and acetic acid in 8.5%, magnification endoscopy alone in 38%, and enhanced magnification endoscopy in all 129 endoscopic areas. The yields for detecting SIM according to endoscopic patterns were as follows: pattern I, 0%; II, 11% (odds ratio 0.5, p = 0.54); III, 87% (odds ratio 36, p = 0.001); and IV, 100% (odds ratio 14, p = 0.015). Conclusions: Enhanced magnification endoscopy is an accurate method of predicting SIM in BE. The simplicity of the technique and its ability to identify characteristic endoscopic patterns with outstanding clarity and resolution that correlate with histologic identification of specialized intestinal metaplasia make enhanced magnification endoscopy an excellent method for the evaluation of patients with BE. (Gastrointest Endosc 2001;53:559-65.)