Despite the significant increase of bryological studies in Spain during the last decades, some regions remain poorly studied. This is the case of Sierra de Gredos mountain range, in the Iberian Central System, which we visited in several collecting expeditions, with focus in the insufficiently explored high mountain areas. As a result, we highlight 28 taxa either by their importance in bryological conservation or because those populations are the first evidence of the taxa in the Iberian Central System. It is remarkable the presence of Kiaeria falcata, never collected previously in the Iberian Peninsula although reported in error based on K. starkei specimens, and Polytrichastrum sexangulare, known so far in the Iberian Peninsula only from the Pyrenees. Likewise, we highlight the new populations of Andreaea nivalis, Anthoceros caucasicus, Kiaeria blyttii, Meesia triquetra, and Polytrichum longisetum. The first one is reported fertile for the first time in Spain. In addition, we found 13 species listed in different threat categories whose number of populations and/or Area of Occupancy (AOO) is inconsistent with the category to that they have been assigned in Spain. Thus, four endangered species proved to be relatively common in the Central System; consequently, we propose to withdraw these species from the list of threatened bryophytes in Spain. This study highlights the urgent need to deepen into the taxonomic and chorological research of Spanish bryological biodiversity to set a solid basis on which an adequate and efficient conservation management may be performed. Finally, taxonomic and ecological comments are indicated for some species.