The paper analyzes the potential benefits of unifying corporate income tax (CIT) in the new member states of the European Union in Central and Eastern Europe (EU10). An analysis based on a review of research reports and the author’s own research shows that equalizing CIT rates across the EU27 could harm EU10 countries, according to Piątkowski. On the other hand, unifying nominal and effective CIT rates in the EU10 at a lower level than in Western Europe—for example in the form of a minimum CIT rate—could produce considerable benefits, especially in the current stage of overcoming the global crisis by countries such as Poland, which aspire to quickly meet the Maastricht fiscal convergence criteria and enter the euro zone. In addition to the direct benefits of tax unification, for example in the form of higher tax revenues, indirect benefits could be generated by shifting international competition from tax policy to the quality of institutions, infrastructure and human capital, Piątkowski says. Reforms in these areas could considerably spur economic growth in the region.