The monotypic rodent Mindomys Weksler, Percequillo & Voss, 2006 (Cricetidae, Sigmodontinae) is one of the rarest members of the speciose tribe Oryzomyini. As this species is restricted to the Chocó forests of the western Andean slope in northern Ecuador, our knowledge is based on a few specimens collected decades ago. Here we add the first data on some aspects of external anatomy (cheiridia examined in fresh, ears, rhinarium), genital anatomy (penis), soft anatomy (palate, stomach, caecum) and postcranial skeleton retrieved from a full adult male, recently trapped in Reserva Drácula, Carchi, Ecuador. Several features of this specimen, paradoxically the first to be added to Ecuadorian mammal collections, reinforce the view that Mindomys is an arboreal sigmodontine.