Branchial cleft cysts and branchial anomalies develop from the branchial cleft apparatus that persists after fetal development. The most common anatomical site for the occurrence of branchial cleft cysts is in the cervical area, generally anterior to the sternomastoid muscle in the upper or middle portion of the neck. A mediastinal branchial cleft cyst is extremely rare and few cases have been reported. We report the case of branchial cleft cyst found in the anterior mediastinum with literature review.