To identify epidemiologic characteristics of definite cases of Ménière's disease (DMD), we conducted retrospective surveys of the period 1990-2004 of the Nishikubiki district and of the period 1980-2004 of Toyama Medical and Pharmaceutical University. Three hundred and seventy-five patients (50 from Nishikubiki, 325 from Toyama) were diagnosed with DMD according to the diagnostic criteria proposed by the Japanese Society for Equilibrium Research. There was a slight increase in the prevalence of DMD during the period 1990-2004. However, incidence did not change significantly over time. The average annual prevalence and incidence were 34.5 and 5.0, respectively, per 100,000 population. Incidence and prevalence predominated in females. With respect to age at disease, the incidence in elderly patients was increased when we corrected for age distribution in the overall population.