An aneurysmal bone cyst (ABC) is a benign tumor of the skeletal system, which most frequently occurs in long bones. An ABC arising from the rib is extremely rare and it is difficult to distinguish from other types of rib tumors. The present study describes an unusual case of a large ABC in the rib of a 17-year-old male. The entity is discussed with particular emphasis on the clinicopathological features, differential diagnosis and treatment. Due to difficulties in the pre-operative diagnosis, a possible diagnosis of ABC should be made aware when confronting an expansile rib mass. An en bloc resection of the mass and the affected portion of the rib is mandatory to obtain a satisfactory outcome.