The pH results of the brine was partially decreased during fermentation. Significant changes were not observed in the pH values of the brine from the beginning of the fermentation to the end of Ayvalık and Gemlik olives, where different methods were applied. In general, the salt content of olive brine of both varieties fluctuated depending on the fermentation time. When the total phenol results of the olive fruits were compared with the control, it was determined that there were significant differences between bitterness treatment processes and cultivars. The total flavonoid results of the control samples of “Ayvalık” and “Gemlik” olive varietis were reported as 1553.24 and 1252.38 mg/100 g, respectively. Total flavonoid results of whole fermented olives of both olive cultivars were plotted and found at higher levels than crushed fermented olives. The total carotenoid contents of fermented olives showed significant differences when compared to the control samples. In general, antioxidant activity values of olives that were debittered with brine, normal water and lye applied to both olive fruits were found to be at considerably higher levels than those treated with caustic. The sensory properties of fermented olives, whose bitterness is removed with lye, were highly appreciated.