Bronchogenic cyst is a rare congenital malformation of the tracheobronchial bud originating from the primitive foregut, especially in the retroperitoneal region. Retroperitoneal bronchogenic cysts in adults are difficult to make an accurate diagnosis preoperatively. We present three cases of retroperitoneal bronchogenic cysts resembling adrenal tumors in adults. Three cases were asymptomatic, and all were located on the left side. There was no significant enhancement of the cyst walls on contrast-enhanced computed tomography. Two cases presented with typical multilocular sacs and scattered calcification on radiology, whereas the other one showed unilocular sacs, without calcification, and elevation of serum carbohydrate antigen (CA) 19-9 and CA 24-2. Three cases underwent retroperitoneal laparoscopic surgeries. Histopathologic examination confirmed the diagnosis of retroperitoneal bronchogenic cysts. There was no recurrence of the three cases during follow-up. A retroperitoneal bronchogenic cyst is mostly asymptomatic. It can be found in adults with variable findings in computed tomography. It can be likely ignored and misdiagnosed as an adrenal tumor. The tests of CA 19-9 and CA 24-2 could help diagnose retroperitoneal bronchogenic cysts. Retroperitoneal laparoscopic surgery is recommended for the treatment of retroperitoneal bronchogenic cysts with a favorable prognosis.