Introduction: Aneurysmal bone cysts recognized since 1893 was described as an ossifying hematoma by Van Arsdale before being recognized by Jaffe and Lichtenstein as an intraosseous, osteolytic lesion in 1942. Bernier and Bhaskar described the first case of ABC in the craniofacial region in 1958. Aims: To find close follow-up is essential to prevent recurrent and relapse. Case Report: It is a benign blood-filled bony lesion affecting the long bones of the human skeleton. They manifest rarely in the head and neck region. They often lead to a delay in diagnosis due to the ambiguity of symptomatology and their rare occurence. Discussion: They should therefore be considered in differential diagnosis of bony, vascular lesions of the head and neck region. Conclusion: Since ABCs can be rare, expansile, rapidly growing and destructive and to make clinicians aware for accurate diagnosis and treatment, we present a case of a mandibular aneurysmal cyst and its management.