Summary: Tax reforms concerning corporate profit are an inevitable phenomenon in the 21st century with the unfair tax competition among countries going rampant. Although not a member of the European Union, Switzerland is affected by these measures, since it is one of the leading economies in the world which profits the most from preferential tax regimes. For the purposes of this study we analyzed the current changes in the tax treatment of corporate profit at all three levels of government in Switzerland which occur due to the Corporate Tax Reform. The paper points to the basic features of the system of corporate taxation in Switzerland in order to understand the changes that followed and the reasons justifying the change in terms of the European Union and the OECD. Accordingly, we propose several key measures that could contribute to the implementation of reforms - for the cantons to accept the international rules or to lower the tax rates on corporate profit to the level of international competitiveness. Aligning the cantonal tax rates has been underway, and in the forthcoming period a referendum is expected to take place with a view to defining further steps in accepting the tax rules. In case that the tax reform III fails, new reforms will be inevitable.