The aim of this study was to determine the effects of different olive processing methods on deltamethrin (DEL), dimethoate (DIM), and imidacloprid (IMI), the most commonly preferred synthetic insecticides for controlling olive pests such as the olive fruit fly. The hypothesis is that the fermentation could accelerate the degradation process of the insecticides. For this purpose, olives were left for fermentation (natural black olives) without and with starter addition (two strains 112 and 123) and processed as dehydrated black olives. To monitor the degradation rate of insecticides, olives were first polluted with the insecticides and then the residues were detected periodically during the processes. The insecticide degradation rates were found to be significantly higher in natural black olives and natural black olives inoculated with both starters compared with those of crude olives and dehydrated black olives. At the end of fermentation (after 60 d), 53-61% of deltamethrin, 66-68% of dimethoate, and 42-50% of imidacloprid were removed in natural black olives and natural black olives inoculated with both starters. In dehydrated olives, the degradation of deltamethrin, dimethoate, and imidacloprid was lower with rates of 9.7, 40, and 13.4%, respectively. The current study demonstrated that natural and starter-added natural black olive processing accelerated the degradation of deltamethrin, dimethoate, and imidacloprid.