Olives, Oleaeuropea (L) (oleacea) are one of the main fruit crops, infested with olive fruit fly, Bactrocera oleae (Rossi). Trials were conducted in olive orchard  at the a  private farms , Ismailia  Governorate ( on Cairo- Ismailia  roadway, Kilo 96), during 2016 season.  The present study was aimed to determine effect of infestation different percentages of Bacterocera oleae to olive fruits on free acidity percentage as oleic acid, peroxide value (P.V.), rancimat, K232, 270 and Validity. The results illustrated that there are highly significant differences between infestation % and acidity percentage, peroxide value and rancimat. Also, the results indicated that there are positive correlation between infestation % and (acidity %, peroxide value) and acid % with peroxide value but there are negative correlation with other treatments. The obtained results revealed that the infestation percentage affect by 99.1, 95.2 and 88.4 %on rancimat, acidity % and peroxide value, respectively. Also, the obtained results showed that acidity percentage and peroxide value increased with increasing infestation %, but augmentation infestation % cause lowest rancimat and validity, where recorded peroxide value was 4.28 meqO²/ kg. Oil in treatment olive fruit free from any infestation compared with olive oil extracted from olive fruits damage4.9 meq O₂/ kg. Wherever, the treatments recorded 4.48, 4.5, 4.51, 4.6, 4.64, 4.67, 4.7, 4.8, 4.85 and 4.9Meq O₂/ Kg. olive oil in case of 5, 15, 25, 35, 45, 55, 65, 80, 90 and 100 % infestation. Also, results of this study showed that K 232 value ranged between 0.15 to 0.23 low from 2.6, while in case of K 270 the values ranged between 1.8 to 2.33nm. Recommendation: The paper recommended use decontrol to reduce injury rates whenever possible to maintain the quality of the oil and augmentation overstocking period.