Aneurysmal bone cysts are rare benign lesions of bone tissue. They are composed of vascular spaces blood-filled and surrounded by fibrous tissue septa. They are considered as pseudo cysts because of lack of epithelial lining. Here, we describe a giant case of ABC in 12-year-old female child having a massive swelling over the right side of the mandible treated with segmental resection and reconstruction with a reconstruction plate. Case is also discussed with the review of literature.