This publication presents a comprehensive treatment of the genus Bromus L. and its occurrences on the Iberian Peninsula. Previously, Bromus had only been given limited attention in a number of floras (e.g. Willkomm, 1861; Losa Espana, 1961). A complete review of literature on the subject is used as the base of this review of Bromus, and nearly 4000 specimens of Bromus were studied and compared to other Bromus specimens from outside the Iberian Penisula. A list of sampling locations of the specimens is provided, documenting the location (UTM coordinates), country, gathering date, ecology, collector and the sheet number of the respective herbarium.