The odontogenic keratocyst (OKC) is unique among odontogenic cysts of the jaws, especially because of the high risk of recurrence. Epidemiological studies demonstrate male predominance and the most common location in the mandible. We reviewed our own experience with eight patients and data in the literature, focusing on very large mandibular keratocysts. We reviewed the clinical, radiological, and histological elements required for the positive and differential diagnosis. CT scans should be performed for very large cysts due to their superiority over plain x-rays, both for treatment planning and follow-up. Surgical treatment is indicated. The choice remains controversial between radical and conservative approach. We prefer conservative treatment. Problems concerning bone healing, recurrence and follow-up are also discussed.