Two unusual cases of achalasia with endoscopic and histologic documentation of Barrett's esophagus are presented. One patient had Barrett's esophagus at the time of initial endoscopy for achalasia, before any treatment. The other patient developed specialized columnar epithelia in the esophagus after treatment with pneumatic dilation. Each patient had evidence of low-grade dysplasia. Including these two patients, 30 cases of Barrett's esophagus in patients with achalasia have been reported in the literature. In 73% (22 of 30) of the cases, Barrett's esophagus was detected after esophagomyotomy. In 20% (6 of 30) of the cases of achalasia and Barrett's esophagus, adenocarcinoma developed. The current two cases are unusual because Barrett's esophagus in achalasia generally develops from gastroesophageal reflux after esophagomyotomy. No other patients have been reported to develop Barrett's esophagus after pneumatic dilation alone. Patients with achalasia and Barrett's esophagus may be at a particularly high risk for developing dysplasia and adenocarcinoma.