Some important olive cultivars like 'Domat' and 'Tavsan Yuregi' are commercially grafted on seedlings which are obtained from open-pollinated seeds of 'Uslu' olive cultivar, which usually produces morphologically uniform populations. In this study, seedling populations of 'Uslu' cultivar were evaluated for their isozyme genotypes. Starch gel electrophoresis for six isozyme systems including malate dehydrogenase (MDH), alcohol deshydrogenase (ADH), isocitrate deshydrogenase (IDH), phosphogluco mutase (PGM), phosphogluco isomerase (PGI) and peroxsidase (PRX) were investigated. Total loci and number of alleles were determined in 50 seedlings. Total 18 alleles were determined at 7 isoenzymatic loci. The seedlings were classified into 9 groups according to their isozyme profiles. ADH and MDH systems were monomorphic among the seedlings. However, PGI and IDH systems were polymorphic due to high level of heterozygosities. PGM and PRX systems exhibited only two isozyme genotypes among the seedlings. This study demonstrates that clonal rootstocks need to be used instead of seedlings for olive cultivars, which have to be grafted for propagation.