We report an unusual hepatoid adenocarcinoma in Barrett's esophagus with achalasia, which developed in a 44-year-old Japanese woman. The patient received an esophago-gastrectomy after diagnosis of the tumor and achalasia at the lower esophagus, 4 months before her death due to multiple metastatic tumors of the liver. The main granular tumor removed surgically was a hepatoid adenocarcinoma, mainly composed of clear cancer cells (alpha-1 antitrypsin, albumin and alpha-fetoprotein positive), with elements of choriocarcinoma and tubular adenocarcinoma. Non-neoplastic specialized columnar epithelium was present extensively near the oral side of the tumor edge in the esophagus, indicating Barrett's esophagus. This unusual tumor was therefore considered to have originated in Barrett's esophagus. The gastroesophageal reflux was presumed to have occurred for a long period, as there was a well-preserved fundic gland in the stomach and a history of frequent vomiting from the patient's youth, accounting for the appearance of achalasia.