The oil results of the scratched “Ayvalık” and “Gemlik” olive varieties on the 0th day of fermentation were determined between 50.01 (lye) and 67.57% (NaOH) to 57.35 (salt) and 72.95% (NaOH), respectively. The oil results of scratched “Ayvalık” and “Gemlik” olives on the 60th day of fermentation were determined between 61.04 (salt) and 64.03% (water) to 55.89 (salt) and 61.95% (NaOH), respectively. While the oil contents of “Ayvalık” and “Gemlik” olive cultivars that were scratched and crushed at the beginning of fermentation (0 day) were higher than the control, the oil results of whole olives were lower than the control. Significant changes were observed in the fatty acid compositions of olive oils depending on the olive variety and the bittering process (p < 0.01). The dominant fatty acids of the oils obtained from olives on the 0th and 60th days of fermentation were oleic, palmitic and linoleic acid. The fatty acid composition of the oils depending on the applied process and olive types differed at days 0 and 60 of fermentation. It can be said that on the 0th and 60th days of fermentation, the oleic acid results of olives of both varieties increased compared to the control. The oleic acid contents of the oils obtained from “scratched” olives of “Ayvalık” varieties at the beginning and end of fermentation varied between 70.10 (NaOH) and 71.66% (lye) to 64.91 (NaOH) and 71.51% (normal water), respectively. It can be seen that debittering processes significantly reduced the amounts of unsaturated fatty acids. In general, it has been observed that olive oils have higher oil contents and better fatty acid compositions. Graphical abstract: The oil content and fatty acid profile distributions of the olives, which give taste and flavor to the olives, must also be monitored before and after fermentation. Research work was carried out to investigate the oil results and fatty acid compositions of the oils obtained from “Ayval?k” and “Gemlik” olives debittered with different solutions and fermented. (Figure presented.)