Despite of the fact that European Union economy is the subject to integration process, there has been no harmonization of corporate income taxation. No compulsion to adapt to common tax law requirements makes that many, especially new member states of EU, tends to use corporate income tax to attract capital flows. The tax competition often takes a form of so called “race to the bottom” and consists in reducing tax rates. At the same time fiscal authorities usually broaden their tax bases in favor to increase the neutrality of the corporate income tax. The main goal of this article is to measure the combined effect of reducing statutory tax rates and broadening of tax bases in selected Member States.