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The mid Cretaceous shallow-water limestones on the islands of Cres and Losinj contain abundant and diversified orbitolinid foraminifera. A biostratigraphy, based on the orbitolinid taxa and their chronostratigraphic interpretation, is proposed for the Aptian, Albian and Cenomanian deposits in the area investigated. Four orbitolinid biozones have been recognized: (1) Palorbitolina lenticularisTaxon-Range Zone in the Lower Aptian; (2) Orbitolina(Mesorbitolina) texanaAssemblage Zone in the Lower Albian, the body of strata being characterized by a distinctive assemblage of Orbitolina(Mesorbitolina) texana, O.(M.)subconcava, O. (M.) parvaand O.(M.) pervia; (3)‘Valdanchella’ dercourtiTaxon-Range Zone in the basal Upper Albian; and (4) Orbitolina(Conicorbitolina) conicaAbundance Zone in the Lower–Middle Cenomanian, a body of strata in which the abundance of the species Orbitolina(Conicorbitolina) conicais significantly greater than is usual in the adjacent parts of the section, regardless of either association or range. The established biozones on the islands of Cres and Losinj are correlated with orbitolinid biozonations and orbitolinid stratigraphic distributions in the adjacent areas, with emphasis on the Karst Dinarides.