The paper discusses the prescription of EU environmental regulations for new member states. It has been argued that these countries should be allowed looser directives as a way to take into consideration their lower income levels and correspondingly different priorities. The paper estimates the determinants of environmental policies' stringency. We find that corruption levels are the most important factor in explaining the variance in environmental policies in the enlarged EU. Most notably, differences in corruption levels across countries appear to be more important than income differences. Thus, it is argued, lower environmental standards in new member states are not necessarily implied by lower income levels, but they are more likely to reflect low institutional quality. We argue that harmonization of environmental policies at the EU level can be a way to tackle this problem, and we provide a further rationale for new members states to adjust to existing EU environmental directives. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.