Monospecific exploitation of reindeer by Neanderthals is common behaviour in the Upper Pleistocene of WesternEurope. However, reindeer-dominated assemblages have largely been reported from regions of northern Germany and south-western France, with few examples noted in south-eastern France, where faunal assemblages are most of the time dominated by a variety of other large ungulates such as red deer, horse and diverse bovids. Here, we present multi- ManuscriptClick here to download Manuscript Daujeard_et_al_Maras_4.1_Text_AAS.docx strand (bio-and eco-) archaeological datasets from the site of Abri du Maras (level 4.1), situated at the mouth of the Ardèche and Rhône rivers, a new example of a reindeer-dominated Neanderthal site in south-eastern France. Dated to the beginning of the MIS 3, the zooarchaeological assemblage is dominated by reindeer (88% of the NISP, representing 16 individuals), but also includes horse, bison, megaceros, red deer, ibex and lagomorphs. The combination of zooarchaeological, cementochronological and tooth microwear analyses evidence a single-species dominated spectrum, with catastrophic mortality and repeated autumnal deaths. This integrated approach provides an extensive picture of human subsistence behaviour, pointing to short-term hunting episodes of reindeer herds in an exceptional context of a quasi-exclusive Neanderthal accumulation. The high number of individuals and selective butchery may correspond with a cooperative and planned mass hunting strategy. The multidisciplinary approach undertaken here also incorporating paleontological, charcoal, ecological, and isotopic analyses places the archaeological and zooarchaeological data within a broader regional palaeoenvironmental framework, providing valuable landscape-contextual information. The zooarchaeological data suggest a subsistence behaviour different from other Neanderthal reindeer-dominated assemblages often connected with specialised butchery or hunting sites.