First described by Philipsen in 1956, the odontogenic keratocyst is characterized by a large squamous keratinization of its border, an aggressive growth and a high recurrent rate. It is now designated by the World Health Organization as a keratocystic odontogenic tumour (KOT). Clinically, the KOT is manifested by an asymptomatic growth. Radiographically, it appears as a well-defined unilocular or multilocular osteolytic lesion. The diagnostic approach is based on a combined analysis of the medical history, the clinical appearance and the radiographic appearance. The diagnosis may be confirmed by the anatomical pathology report. Finally, treatment consists of surgical excision and follow up is characterized by a high rate of recurrence. The authors report a case of keratocystic odontogenic tumor of the upper jaw and review the various diagnoses, therapeutics and follow up aspects of this type of tumors.