Abstract: Olive fruit fly is one of the most important olive pests in the world. The pest invadedthe olive growing regions of Qazvin (Tarom Sofla), Iran, in 2004 and soon became a major pestdamaging economically the olive orchards in all infested regions. The olive fly larvae causequalitative and quantitative reduction of olive oil by entering to fruits flesh and exposing them topathogenic fungi. However, the degree of this reduction may vary especially considering theduration of fruits storage from harvest until oil extraction. Therefore, the current research wascarried out to compare the effect of storage time of infected from Bactrocera oleae olive fruits onthe olive oil characteristics. The experiment was designed in a RCBD with six treatments andthree replications, on Zard olive cultivar. Treatments included healthy fruits immediately afterharvest as control, infected fruits immediately after harvest and infected fruits 1, 2, 3 and 4 weeksafter storage. The oil was extracted by centrifuging the fruit flesh samples. Then, the oil sampleswere coded and sent to Oil Seed laboratory, Seed and Seedling Improvement Institute for furthermeasurements on their quality. The results revealed that acidity of the oil was not significantlydifferent among healthy fruits (control) (0.630%) and infected fruits either immediately (0.547%)or 1 week after storage (0.777%) which had comparatively lower acidity and higher quality.However, the significantly highest oil acidity was observed in the infested fruit treatments 3 and 4weeks after storage (5.070% and 7.627% respectively) that showed sever reduction in oil qualityin these treatments compared with that of others.