The knowledge of species occurrence within an area is crucial to develop proper conservation strategies to protect species diversity. Biosphere Reserves (BRs), established to preserve biodiversity and sustainably use their resources, should therefore have precise information of its biodiversity. We compared and evaluated information on threatened and non-threatened vertebrate species available for Spanish BRs from three sources: management documents (MDs), the Global Biodiversity Information Facility index (GBIF), and atlases and red books. Our results suggest that information from any one source was rather partial, to a degree that depended on which vertebrate group was considered. Management documents did list a high percentage of threatened species found in BRs, reaching up to the total number of species of birds and mammals. Species lists overlap between all three sources ranged from 59 % for fish to 84 % for mammals. In addition, there is an inconsistency between national and international threatened species categories and it should thus call for revisions. Even though the information of non-threatened and threatened species occurrence in MDs of Spanish BRs is good, it is necessary to pay attention to amphibian and fish species which are less recorded.