Numerous epidemiologic investigations have been conducted regarding the incidence of Menière's disease, but the values obtained for different countries vary greatly. This can be attributed to the fact that different criteria have been applied in defining Menière's disease. The objective of this study was to evaluate the incidence and prevalence of Menière's disease in Italy following the American Academy of Ophthalmology and Otolaryngology guidelines. A total of 111 cases with Menière's disease were diagnosed in a district of southeastern Latium over a 13-year period, with an incidence of 82 per 10(6). A figure 3.4 times greater was found in hospital personnel, thus showing that a greater availability of medical facilities increases the number of diagnoses. Sex was found not to be a determining factor. The authors suggest that the incidence reported in this paper is an underestimate and that the actual one remains undetermined, but probably higher than generally believed.