Description of a new species of Uroseius Berlese based on deutonymph and female specimens from northern Spain is presented. Observations of some cuticular organs on idiosoma and legs are described for the first time for the genus. An attempt to notate idiosomal setae as in Gamasina mesostigmatid mites is made based on complete dorsal chaetome of larval and pronymphal instars of Uroseius and Apionoseius Berlese species. Uroseius acuminatus (C.L. Koch) is a new record for the Iberian Peninsula. General morphological and biological aspects of Uroseius are presented. A tentative key, provided for separation of the 15 deutonymphs and nine adult females of the world species of Uroseius, is given.