OBJECTIVES:  To estimate the prevalence of insulin-treated diabetes in French regions and sub-regions (2016, current year). METHODS:  A retrospective cross-sectional analysis of National Health Insurance claims databases was performed (2013, most recent year available). The number of pharmacologically-treated diabetic patients was available for each region and sub-region as an open dataset extracted from the comprehensive claims database (SNIIRAM, 2013) of the French National Health Insurance Fund (Cnamts) and published on the French Institute for Public Health Surveillance (InVS) website. Regional estimates of the prevalence of insulin-treated diabetic patients among pharmacologically-treated diabetic patients and the distribution between type 1 and type 2 diabetes (T1D/T2D) in insulin-treated diabetic patients were computed through an ad-hoc analysis of a permanent, representative sample of the SNIIRAM (EGB, 2013). For each region, estimates were extrapolated to its related sub-regions, assuming homogeneity within the region. Projections (2016) were performed using two different compound annual growth rates, one for the general population and one for the pharmacologically-treated diabetic population, assuming stability of other parameters over time. RESULTS:  Estimates (2013): 63,786,000 inhabitants in France, 2,941,000 patients pharmacologically treated for diabetes (national prevalence: 4.6%), of which 693,000 patients treated with insulin (national prevalence: 23.6%), including 551,000 T2D/142,000 T1D patients (national distribution: 79.5%/20.5%). Projections (2016): 64,594,000 inhabitants in France, 3,148,000 patients pharmacologically treated for diabetes (national prevalence: 4.9%; regional prevalence range: 3.4%[Bretagne] - 5.5%[Nord-Pas-de-Calais-Picardie]; sub-regional prevalence range: 2.9%[Ille-et-Vilaine] - 6.9%[Nièvre]), of which 745,000 patients treated with insulin (national prevalence: 23.7%; regional prevalence range: 21.8%[Aquitaine-Limousin-Poitou-Charentes] - 25.7%[Bretagne]), including 591,000 T2D/154,000 T1D patients (national distribution: 79.3%/20.7%; regional distribution range: 75.9%/24.1%[Bretagne] - 83.8%/16.2%[Alsace-Champagne-Ardenne-Lorraine])