The objective of this study was to identify a local olive cultivar Gerboui based on biometric characteristics. All the experiments were conducted in selected olive grove situated in northern part of Tunisia (Testour and Thibar) where the most widespread variety is Chetoui following by Gerboui which is a local variety. The experimental approach was based on using 32 parameters as recommended by COI for characterization and the bioagronomic observations concerned the morphological characteristics of the trees, leaves, fruit and inflorescence and the flowering period. The olive fruits were examined for their morphology and oil composition (oil content, oil quality and maturity index) and for endocarp characteristics. The field comparison, carried out in 2003, 2004 and 2005 and in the 2 regions, showed a good vegetative and reproductive behaviour of this cultivar, good productivity with high oil content and quality (fatty acids based on IOOC standards). Flowers occurred on inflorescences that measured about 3 cm in length. On average 23 flowers were observed by inflorescence but 42% were aborted which is acceptable for obtaining a commercially profitable crop in olive trees. Inflorescence length, number of flowers per inflorescence and pistil failure percentage resulted higher in Testour than in Thibar. The parameters of pollen capacity studied indicate that the pollen of Gerboui olive cultivar show a rapid germinative capacity and a good growth of the pollen tube, which is suitable as pollinizer. Olive oil of cultivar Gerboui is considered to be highly nutritional oil due in part to the high level of monounsaturated oleic acid and lower palmitic and linoleic acid content. The fruit samples had oil yields greater than 18% (25%) calculated at 50% moisture, oleic acid levels greater than 55% (60.5%), palmitic acid between 7.5 and 20% (13.4%) and linolenic acid levels less than 1% (0.55%). The self fertility behaviour of this olive cultivar shown it is self-compatible, with satisfactory fruit set when flowers were self pollinated. The fruit set in self pollinated flowers was 3.12% resulting in higher fruit set in free pollinated flowers 4.21%. It has shown compatibility to local climatic conditions and was well adapted to the cultural and environmental conditions of the site. This description analyses numerous characters of local cultivars which can solve some cases of varietal homonymy and synonymy, resolving the confusion in cultivar identity. This can also assist olive producers in making informed varietal choices from the comparative physiological information on the performance of local olive cultivars in Tunisia.