Consumption of olive oil has been constantly increasing, with worldwide olive oil production almost doubling in the last 20 years. Similarly, in Croatia, the area under olive cultivation has been continuously growing in the last two decades, and annual average olive fruit production went from 16 000 tons from the beginning of nineties to 39 000 tons in recent years. Given an increasing demand by consumers for high quality oil with a clear regional identity, olive oil producers have started to emphasize the origin of their oil, usually through a protected designation-of-origin label. At the same time, however, olive oil is considered to be one of the most mislabeled products in Europe. Hence, oil origin determination has become a question of great scientific interest and economic importance in main olive-producing countries in Europe. The aim of the proposed research is to develop the standard methodology for reliable determination of the olive oil origin. The main objective is to gain knowledge on the role of soil-related factors as well as agricultural management in relevant Croatian environments in influencing elemental and isotopic composition of olive oils. Our novel approach is aimed at quantifying and characterizing the major influences that affect applicability of the geographic traceability technique. We will characterize in detail elemental and isotopic composition of oils as influenced by topsoil and subsoil elemental profile and the effects of cultivar, soil moisture and fruit maturity at harvest. In practice, this project will create (i) key documents to be used for determination of origin of olive oil in Croatia in the future, and (ii) a scientific network that will connect our young researchers around the new research subject, and increase the institutional capacities and personal capabilities in the methodology for ascertaining geographic origin of olive oil – an area that is currently non-existent in Croatia. Croatian oils are getting increased national and international recognition and awards. This project will provide a reliable tool for Croatian olive industry in applying and controlling protection of geographic origin. Differentiation based on specific links between olive oil and the properties of the originating region would increase security in the provenance of the product. This would provide a stimulus for a more profitable production of olive oil – the most important agricultural product of the Mediterranean Croatia.