In order to recognize and verify the lower Miocene deposits and the Aquitanian-Burdigalian boundary, benthic foraminifera from different localities in the north of the Central Iran Zone are considered. These facies-controlled foraminifera are useful for biostratigraphical studies, especially in the absence of planktic foraminifera. We investigated eleven stratigraphic sections of the north and northwest Central Iran Zone, and found datum levels of benthic foraminifera such as Borelis melo curdica, Peneroplis farsensis, Elphidium sp. 14, Meandropsinaanahensis, Meandropsina iranica, and Austrotrillina howchini. The most significant event is the first occurrence of Borelis melo curdica which appears at the beginning of the Burdigalian. Hence, this datum can be helpful to recognize the Aquitanian-Burdigalian boundary.