Radicular cysts are the most common cystic lesions of the jaw. Most of these lesions involve the apex of the offending tooth and appear as well-defined periapical radiolucencies. This case presents an unusually large multilocular radicular cyst crossing the midline and involving almost the entire body of the mandible. The clinical and radiographic appearance mimicked an aggressive cyst or benign tumor. The lesion was surgically excised, and the teeth were endodontically treated without any postoperative complications. Keywords: multilocular radiolucency, periapical radiolucency, radicular cyst