The paper analyzes the euro currency and its introduction, as well as the impact after its introduction on the territory of the Republic of Croatia. The impact of the euro on the development of the economic market after its introduction was investigated. During the research, it will be possible to display the thinking of the respondents, which advantages, disadvantages, impacts on the economic market they think are present after the introduction of the euro. Research will be made possible based on survey questions. The theoretical part of the development of the European Monetary Union as well as the eurozone and the euro is briefly described in order to make a closer comparison with the real situation. The internal market in the European Union will be presented, as well as its freedoms and competitions that are present. The introduction of the euro in the Republic of Croatia is described in three stages, the first brings the advantages and disadvantages of the introduction. The second phase enables the presentation of the strategies that were implemented during the introduction of the euro, and at the end the overall situation after the introduction of the euro will be reviewed. Economic development in the Republic of Croatia is described through conversion costs and business risks, and how much their contribution is in a positive or negative context.