"The prospect of joining the European Union defines much of Poland's current policy agenda. The political and economic consensus in favor of joining the EU as quickly as possible is very strong, and indeed, most of the adjustments required are likely to be in Poland's immediate interest. However, the changes required to comply with EU directives in the environment sector involve sustained high levels of investment and significant uncertainty about the timing and nature of the associated benefits."The European Commission's Opinion on Poland's application for EU membership acknowledges the severity of the environmental problems in Poland and comments on the challenges the country will have to face, especially in the areas of wastewater treatment and air pollution. The Opinion concludes that while full transposition of the environmental acquis in Poland could be expected in the medium term, effective compliance with a number of pieces of legislation would require sustained high levels of investment and considerable administrative effort. Full compliance in areas such as drinking water and certain aspects of waste management could be achieved only in the long term and will necessitate increased levels of public and private investment.This paper aims to address some of the issues involved in planning compliance with EU environmental directives. The paper has three principal objectives: • Highlight major issues that Poland is likely to face in implementing the requirements; • Estimate the total costs of compliance for the public sector in certain key sectors, and outline possible options for reducing those costs; and • Assess where the burden of those costs is likely to fall, and the options for financing the investments.