FORMIDABEL is a database of Belgian Ants containing more than 27.000 occurrence records. These records originate from collections, field sampling and literature. The database gives information on 76 native and 9 introduced ant species found in Belgium. The collection records originated mainly from the Ants collection in Royal Belgian Institute of Natural Sciences (RBINS), the ‘Gaspar’ Ants collection in Gembloux and the zoological collection of the University of Liège (ULG). The oldest occurrences date back from May 1866, the most recent refer to August 2012. FORMIDABEL is a work in progress and the database is updated on a regular basis. Twice a year the database is updated with data from the North and the South of the country. The latest version of the dataset is publicly and freely accessible through this url: http://ipt.biodiversity.be/resource.do?r=formidabel. The dataset is also retrievable via the GBIF data portal through this link: http://data.gbif.org/datasets/resource/14697 A dedicated geo-portal, developed by the Belgian Biodiversity Platform is accessible at: http://www.formicidae-atlas.be FORMIDABEL is a joint cooperation of the Flemish ants working group "Polyergus" and the Wallonian ants working group "FourmisWalBru". The database was created in 2002 in the context of the preliminary red data book of Flemish Ants (Dekoninck et al. 2003). Later in 2005, data from the Southern part of Belgium; Wallonia and Brussels were added. Twice a year the database is updated with data from the North and the South of the country. FORMIDABEL is a work in progress and the database is updated on a regular basis. The latest version of the dataset is publicly and freely accessible through this url: http://ipt.biodiversity.be/resource.do?r=formidabel All the records in FORMIDABEL are georeferenced through the centroid coordinates of the corresponding UTM 5 Km square. Therefore, the uncertainty of these coordinates is 3.500 meters, the distance between the centre and the corner of the UTM square. FORMIDABEL follows the taxonomy of Seifert (2007) for most genera and Radchenko & Elmes (2010) only for the genus Myrmica. A dedicated geo-portal showing Formidabel records is accessible at: http://www.formicidae-atlas.be/