Abstract: Background: The chemical composition of olive oil will change re- garding to cultivar, ripening stage and edaphoclimatic regions. The effect of two edaphoclimatic regions (Fasa and Tarom), two fruit ripening stages (purple and black) and three olive cultivars (Arbequina, Koroneiki, and Roghani) were stud- ied. Methods: Some functional physicochemical properties (fruit weight, ratio of flesh/stone weight, fruit size, oil content, fatty acid composition, and nutritional indexes) for three olive cultivars were tested. Results: The statistical results indicated that the average weight of fruit in Tarom is higher than that in Fasa. Oil content reduced during maturity period in both regions in Koroneiki (43.20 to 33.75% in Fasa and 36.91 to 34.16% in Tarom) and in Roghani of Tarom (48.97 to 42.97%), while the value increased in Roghani of Fasa (22.19 to 30.57%) and remained unchanged in other samples. The oleic acid is higher than other fatty acids in all cultivars and regions, while in- creased in Koroneiki of Fasa and decreased in Arbequina and Roghani of Fasa and Tarom and Koroneiki of Tarom during maturity period. The ratio of 3/6 during maturity period decreased in all samples except in the oil from Koroneiki of Fasa and Roghani of Tarom. The PUFA/SFA in- creased in the oil from Arbequina of Fasa (0.80 to 0.86) and Koroneiki (0.53 to 0.63 and 0.42 to 0.49) and Roghani (0.66 to 0.94 and 0.78 to 0.90) of Fasa and Tarom, respectively, while decreased in Arbequina of Tarom (0.71 to 0.69). Conclusion: In most samples, fruits in last ripening stage have lower content of oil, mois- ture, F/S ratio and oxidative stability. So, in order to produce high yield and quality olive oil, recommended that, olive fruit harvesting was done before the end of complete maturity progress, in purple stage
