This study was carried out between 2016–2017 to identify local olive varieties grown in the Derik district of Mardin province and their distinguishing characteristics. In the study the growing strength of the trees of eight local olive species, pomological characteristics of their leaves, inflorescence, fruit, and seeds, phenological development periods, total oil content, fatty acid composition, and sensory characteristics of their oils were examined. It was found that the “Mavi” variety had the highest values for fruit weight, width, and flesh ratio among the varieties examined. The variety with the highest fruit oil content (30.0%) was “Derik Halhalı”, followed by the “Melkabazi” variety with oil content of 26.0%. The most abundant fatty acid in the oils of local olive varieties was cis-Oleic acid (57.60–73.51%), followed by Palmitic acid (12.90–18.57%), cis-Linoleic acid (7.97–17.76%), and Stearic acid (2.48–3.30%). It has been determined that growing “Derik Halhalı” and “Melkabazi” as oil genotype is suitable, while growing “Zoncuk”, “Mavi”, “Kejik”, “Belluti”, “Hursiki” and “Gulleki” as table genotype is suitable