The flying squirrels (Sciuridae, Pteromyini) from the late Miocene (MN9, early Vallesian) site of Can Llobateres 1 (Vallès-Penedès Basin, Catalonia, Spain) are represented by up to five different taxa: Albanensia aff. grimmi, Miopetaurista neogrivensis, Miopetaurista crusafonti, Blackia miocaenica and cf. Pliopetaurista sp. Miopetaurista crusafonti is by far the most abundant flying squirrel, and an emended differential diagnosis for this species is proposed on the basis of the rich collection from Can Llobateres 1. The presence of Blackia miocaenica and cf. Pliopetaurista sp. at this site deserves special attention because these taxa have not been previously reported from Spain during the Vallesian. Despite their extreme rarity in the Vallès-Penedès Basin, evidence indicates greater faunal affinities with the Central European forest faunas than with other regions. Indeed, flying squirrels are not recorded from any other Spanish site during the Vallesian, which supports previous studies which have shown that Catalonia represented a transitional area between Central Europe and the drier and less forested regions of inner Spain. The brief occurrence of B. miocaenica and cf. Pliopetaurista sp. at Can Llobateres 1 might be explained by the short-lasting presence of favourable environments, although the available data do not indicate any major environmental change. Alternatively, we suggest that their presence is likely related to the enormous sampling effort devoted to this site, allowing for the recovery of very rare taxa. Therefore, these flying squirrels would have a longer range in the area but would have very specific ecological requirements, which, in turn, would account for their rarity.