Introduction: Ameloblastoma is a clinically benign and locally aggressive tumor of odontogenic origin. The tumor exhibits a variety of biological behaviors from a small cystic expansion to a large aggressive mass which is invasive, recurrent and may also show malignant transformation. Case Report: This paper reports a unique case of a female patient with giant ameloblastoma of the mandible. Radiograph revealed an enormous swelling of the left side of the face, resorption of the affected hemi-mandible. Pressure from the tumor resulted in displacement and destruction of the facial skeleton. The patient was treated by radical hemimandibulectomy with removal of the tumorous mass. Conclusion: Ameloblastoma of the mandible and maxilla is generally a benign tumor of the odontoma with locally aggressive behaviour. Post operative radiotherapy for patients at increased risk of local recurrence improves local tumor control.