Bronchogenic cysts are among developmental disorders of the primitive foregut which are typically found above the diaphragm. Bronchial cysts discovered in the abdominal cavity or retroperitoneum are extremely rare. We present a rare case of a retroperitoneal bronchogenic cyst which was incidentally detected after a wrestling injury in a 23-year-old man who had a negative medical history. Although initial imaging studies suggested an adrenal tumor, histopathological analysis provided a definite diagnosis of bronchogenic cyst. Though rare, bronchogenic cysts must be considered in the differential diagnosis of retroperitoneal cystic lesions. This is the first case of a retroperitoneal bronchogenic cyst reported in Iran.