BACKGROUND: Keratocystic odontogenic tumor (KCOT) is a rare, benign, intraosseous tumor of odontogenic origin with a potential of aggressive and infiltrative behavior. It shows specific histopathological features, and has a high recurrence rate. CASE DETAILS: The presented case was of a 30 years old man from South Ethiopia, with a giant keratocystic odontogenic tumor of the mandible. CONCLUSIONS: Although the occurrence of KCOT is rare, attention should be given during its clinical diagnosis. In this report, we presented the aggressive surgical management of a KCOT in a 30 years old patient with no evidence of recurrence within six monthsof follow-up.