Abstract: This study comprises of modal and petrographical results of Elmedin hill reef and Kızılkaya hill reefcomplex that are situated approximately 4-5 km northeast of Mut town (Mersin). In the Mut basin, Mut formation, that contains reef limestone (Middle Miocene) has a lateral and vertical gradational contact with Köşelediformation which includes claystone-marl-clayey limestone alternation and deposited in among the reefs and relatively deeper region in the basin. The Mut formation unconformably overlies the Late Cretaceous limestone andBurdigalian aged Derinçay formation that contains fluvial and limnic deposits and Aqutanian-BurdigalianFakırca formation which contain limnic deposits.As a result of petrographical studies, three fades are distinguished in Kızılkaya hill reef complex andElmedin hill reef and surrounding sediments. According to modal analysis results, micrit: 60.4 %; sparit: 4.1 %;frame forming organisms: 18.7 %; intraclast: 5.3 %; other constituents: 11.5 % in average volume are found inthe base fades (wackestone-packstone). In reef core fades; in bindstone-framestone subfacies micrit: 26,4 %;sparit: 18.4 %; frame forming organisms: 43.5 %; intraclast: 3.5 %: other constituents: 8.1 %; in wackestonepackstone subfacies micrit: 48.8 %; sparit: 12.2 %; frame forming organism: 5.7 %; intraclast: 12.3 %; otherconstituents: 21.1 % are found. In sealing fades (wackestone-packstone) micrit: 54.8 %; sparit: 7.5 %; frameforming organism: 16.8 %; intraclast: 7.3 %; other constituents: 13.7 % are determined.Ratio of frame forming organisms (coral+red alga+bryozoa) were constant during the stable sea leveland suitable environmental condition. When high stand sea level; ratio of frame forming organism was relatively decreased, binding materials was increasing. Other constituents and depend on an effect of sea wave intraclastwere reach to significant ratio.