Two cases are presented of a central odontogenic fibroma (OF) in the mandible of a middle-aged female, which posed considerable difficulty in microscopic diagnosis. These well-demarcated but non-encapsulated intraosseous tumors had hybrid features of both OF and ameloblastoma. Their clinical findings are more in keeping with the putative OF rather than ameloblastoma. The present lesions alert pathologists to this unusual type of central OF in order to avoid misdiagnosis.