Congenital posterolateral diaphragmatic hernia is rarely reported in adults. The adult type is usually found on the left side, and in most instances there is no peritoneal sac. The symptoms for this lesion are referable to the G-I tract and not the respiratory system, although 25% of reported adult cases are symptom free. The best way to manage this disease is immediate operation after diagnosis. This article presents a rare case, which is the second reported case in Taiwan.