Ameloblastoma is a neoplasm of odontogenic origin. Although it is considered a benign lesion it presents some peculiarities including a high local recurrence rate, particularly after conservative surgery, and a high loco-regional invasiveness. The present work describes a case of ameloblastoma of the left maxillary sinus bordering on the homolateral nasal fossa. The male patient was admitted to the E.N.T. Dept II of the University of Turin in May 1998 and underwent left radical maxillectomy. The authors also review the literature on the topic.