Our objective was to assess the incidence of amyotrophic lateral sclerosis (ALS), and its temporal variations, between 1997 and 2007. The study was based on data prospectively gathered by the referral ALS 'expert centre' of the Regional University Hospital of Limousin (710,792 inhabitants). Patients were included if they were diagnosed with ALS according to the revised El Escorial criteria either at the time of diagnosis or at subsequent follow-up, and if they resided in Limousin when diagnosed. We identified a high crude incidence (2.5/100,000). When age-standardized for the 1999 French population, the mean annual incidence was 2.0/100,000 inhabitants (95% CI 1.8-2.3) overall and 4.4 (95% CI 3.6-5.2) in the 45-74 years age group. Crude incidence by age groups showed a progressive increase up to 85 years, followed by a sharp decrease thereafter. Age at diagnosis was particularly high in our population (median, 69.4 years). Incidence of ALS in Limousin was consistent with previous work published by European population-based registries. The atypical epidemiology was explained in part by Limousin's older aged population. It is proposed that our referral centre will become a population-based registry.