a b s t r a c tThe subsistence of hunter-gatherers in the Mediterranean Basin has been the object of few studies, which have not fully clarified the role of aquatic resources in their diets. Here we present the results of AMS radiocarbon dating and of isotope analyses on the earliest directly-dated human remains from Sicily, the largest island in the Mediterranean Sea. The radiocarbon determinations show that the Upper Palaeolithic (Epigravettian) humans from Grotta di San Teodoro (15 232e14 126 cal. BP) and Grotta Addaura Caprara (16 060e15 007 cal. BP) date to the Late-glacial and were possibly contemporary. The diets of these individuals were dominated by the protein of large terrestrial mammalian herbivores, such as red deer (Cervus elaphus). There is no evidence for the consumption of marine resources, which is probably the result not only of the oligotrophic nature of the Mediterranean, but also perhaps of the lack of adequate technology for exploiting intensively the resources from this sea. In spite of being contemporaneous and of the cultural and technological affinities present between the San Teodoro and Addaura humans, the carbon (d 13 C) and nitrogen (d 15 N) isotope composition of their bone collagen suggests that significant differences were present in their diets. In particular, the hunter-gatherers from Grotta di San Teodoro, in NE Sicily where coastal plains are backed by high mountain chains (Monti Nebrodi), probably had easy access to resources such as anadromous brown trout (Salmo trutta), which might not have been similarly available in the NW of the island, where reliefs are noticeably lower and watercourses fewer and farther between. This study shows that the high biodiversity of this region, which results from the complex topography of Mediterranean landscapes, was probably exploited opportunistically by Lateglacial foragers. Our data also suggest that intensification and diversification of food acquisition in Sicily did not start in the closing stages of the late Pleistocene, as in other Mediterranean regions, probably because the island had only been (re-)colonized by humans around the Last Glacial Maximum.