Incidence of Ménière's disease has been the subject of many epidemiologic papers in Literature. Nevertheless, it varies greatly in studies from different countries and it is unclear to what degree these differences can be attributed to epidemiologic differences and to what degree to problems of methodology (selection and assessment of the patient). The objective of this paper is to evaluate the incidence of Ménière's disease in the USL district 30 of the Siennese Area following definite and easily reproduced criteria. A total of 33 new cases of Ménière's disease was identified during a 10-year period from 1981 to 1990. Thus, in relation to the total number of residents in the USL 30 of the Siennese Area (120,000), the average annual incidence rate may be calculated at 27.5 x 10, a relatively modest figure in comparison with other studies. Given this, the Authors discuss the methodological problems relative to the epidemiological assessment.