With the step up of globalization and integration process, the importance of taxes and tax policy increase. Taxes are important factor in taking investment decisions and they are continuously analyzed regarding theirs efficiency, fairness, simplicity, transparency and fiscal profusion. Respectively, they are subject to constant changes. Especially complex are income and capital gain taxation systems. Mentioned tax forms, besides theirs economic and social importance, have also very expressed fiscal meaning. Today, more and more attention is dedicated to capital gains tax. Taxation of capital gains is connected with a series of theoretical and practical problems. In theory, it is considered that capital gains should be the subject of taxation because they are one of possible source of income. But in different countries practices, approaches to capital gains taxation vary. It should be considered that eventual implementation of capital gains taxation has notably considerable economy impact, while social and fiscal impacts could be relatively small or almost negligible. The goal of this research is to indicate possible implications of capital gains taxation implementation in Croatian tax system. Through the analysis of this tax form it will be demonstrated differences in capital gains taxation treatments in EU countries, it will be isolated potential advantages and disadvantages of this tax form, and established possible implications on further financial market development in the Republic of Croatia. Based on this analysis, authors will try to reach valid conclusion on adequacy of its implementation in Croatian tax system. Besides that, research proceeds can find theirs implementation in the process of (fiscal) adaptation and association of Republic of Croatia to the European Union.