:This study addresses the many issues surrounding implementation of environmental measures in Central and Eastern Europe. Through case studies of these issues in Poland and Ukraine, it evaluates the environmental behaviour of industrial polluters and highlights the regulatory processes in the post-communist context. The findings reveal that membership in the European Union is the primary driving force behind business environmental performance in countries under investigation. Interestingly, the EU's impact does not necessarily depend on the stringency of its norms. These are instead procedural requirements that accelerate the implementation process. Nevertheless, EU membership is not the only factor which stimulates environmentally aware behaviour. The analysis has shown that market forces are important stimuli even in the absence of EU external pressure. « .» (¿Ukraine is on the brink of an ecological disaster.¿) Ukrainian Environmental League, Zhytomyr Regional Office, March 2006 In 1990, Ukraine emitted over 923,000 Gg of greenhouse gases into the atm- phere. Out of Annex I Parties to the Kyoto Protocol only United States, Russia, Japan and Germany reported higher pollution levels. Interestingly, annual em- sions in Ukraine have dropped by almost 55% in recent years and reached 419,000 Gg in 2005. None of the world¿s heaviest polluters can boast such a massive reduction in annual greenhouse gas emissions. However, even with a clear 30% reduction, Poland¿s progress as an en- ronmentally responsive new European Union (EU) member state is evidently behind that of Ukraine. While Poland reported 485,000 Gg of greenhouse gases 1 emissions in 1990, this figure fell to 399,000 Gg in 2005. Ukraine would seem at first glance to have achieved greater progress in the environmental policy context than Poland. Not only has Ukraine reduced its greenhouse gas emissions by more than 50%, it is also no longer in the group of the world¿s ten heaviest polluters. Nevertheless, Ukrainian environmental Non-Governmental Organisations (NGOs) openly declare that their homeland is ¿a country on the brink of an eco- 2 logical disaster.¿ In contrast, Poland is no longer being considered ¿a country of ecological catastrophe¿ (Ministry of Environmental Protection, Natural - sources and Forestry 1991). It is even being described as a new EU member state that ¿made a remarkable environmental progress¿ (OECD 2003).