Invasive Alien Species (IAS) are one of the five major causes of biodiversity loss worldwide. Given their diversity and abundance, it is not feasible to act on all IAS. The EU Regulation 1143/2014 and the 2017 national IAS strategy provide a framework for preventing the introduction and spread of IAS and managing them. The Conservatoire d’Espaces naturels d’Occitanie has developed and is now leading the regional strategy for IAS fauna in Occitanie, aiming at guiding and coordinating management actions on animal IAS. To this end, an inventory of the knowledge of IAS fauna occuring or likely to be introduced in Occitanie has been carried out. There is currently no standardised method shared by all stakeholders to classify IAS fauna according to the threat they represent. An integrative method was therefore developed based on four international and regional standardised methods (EICAT, SEICAT, ISEIA, ISSIA) in order to categorise exotic species in Occitania according to their invasion potential and their ecological, socio-economic and health impacts. The objective of this article is to share our feedback on the development of the method for the elaboration of the categorized list, and on the possible applications of the latter. In particular, we show how regional stakeholders can appropriate the categorized list, which constitutes the first knowledge tool on IAS fauna in Occitanie. The categories thus defined, combined with the expert hindsight according to the context, make it possible to identify the main types of action to be taken on these species (prevention, management, improvement of knowledge, communication). This work could serve as a basis for the development of similar tools in the other regions planning to implement the national strategy.