A man in his thirties with epigastric pain was referred to our hospital for detailed examinations. Abdominal computed tomography showed an abdominal cystic lesion with a longest dimension of 7 cm, located behind the stomach. Endoscopic ultrasonography through the stomach showed a cystic lesion and the wall of the lesion revealed continuity to the proper muscle layer of the gastric wall. Therefore, gastric duplication was suspected and the cystic lesion was resected because of the possibility of malignancy and also for a definitive diagnosis. The cystic lesion consisted of columnar ciliated epithelium, seromucous glands, smooth muscle and cartilage and was diagnosed as a bronchogenic cyst. Bronchogenic cysts are sometimes encountered in the thoracic or mediastinal area, but abdominal bronchogenic cysts, such as the present case, are extremely rare.