Background and objective: The composition of olive oil is significantly affected by the cultivar and climatic conditions. The present study determined the chemical characteristics of olive oil extracted from two major Iranian varieties of olive (yellow and local oil-grade) in Shiraz and Kazeroon, two major olive producing areas in Fars province.Materials and methods: The composition of olive oil is significantly affected by the cultivar and climatic conditions. The present study determined the chemical characteristics of olive oil extracted from two major Iranian varieties of olive (yellow and local oil-grade) in Shiraz and Kazeroon, two major olive producing areas in Fars province.Results: The results showed that the physical and chemical properties of both cultivars are in accordance with national and international standards. There was a significant difference in acidity, iodine content and peroxide content between cultivars (P<0.05) in both regions, but the differences between saponification and nonsaponifiable matter were not statistically significant (P³0.05). The oleic acid content of the yellow cultivar was higher than the local oil-grade, and the palmitic, palmitoleic, linoleic, and linolenic acid content in the local oil-grade was higher. There was a positive correlation between oleic acid content and temperature. The oleic acid content of the local oil-grade cultivar in Kazeroon was lower than codex standards and the yellow cultivar of Shiraz had the highest oleic acid content.Conclusion: The superior quality of the yellow cultivar of Shiraz, which had the highest oleic acid content (75%) and lowest linoleic acid content recommends it as the best variety. The inferior quality of the local oil-grade olive is demonstrated by its low oleic acid content and high linoleic acid content. These results indicate that the quality of the olive oil depends both on the olive cultivar and geographical region.