The aim was to review previous cases of Odontogenic Keratocyst or Keratocystic Odontogenic Tumor according to the new WHO classification. We used all cases diagnosed as Odontogenic Keratocyst or Keratocystic Odontogenic Tumor registered in the archives of the Pathologic Anatomy Laboratory of the Department of Pathology and Oral Diagnosis of the School of Dentistry of the Federal University of Rio de Janeiro, Rio de Janeiro, Brazil, which were collected from September, 1983 until September, 2008. The terms “Keratocyst” or “Keratocystic Odontogenic Tumor” were searched for and the following data were collected from the case files: age, sex, location of the lesion(s), and patients’ chief complaints. Hematoxilin and Eosin slides were reviewed according to the 2005 WHO criteria. The results found are in accordance with the literature. Due to its benign features, the Orthokeratinized Odontogenic Keratocyst found in our sample had its diagnosis changed to Orthokeratinized Odontogenic Cyst, as recommended by the WHO. Histopathologic exams are required for every bone lesion, in order to establish correct diagnosis. Because of its features, the Keratocystic Odontogenic Tumor must have more aggressive treatment, compared with odontogenic cysts, and long-term follow-up is mandatory.