In the Accession Treaty of 16 April 2003, Poland agreed to adopt euro as its national currency, but the date of this adoption was not specified. The financial crisis in several countries of the Eurozone, in response to the world financial crisis in 2008, reduced drastically the public support in Poland for the replacement of the zloty by the euro. This article has two objectives. One is to assess the net costs, economic and political, for Poland remaining long outside the Eurozone. In this assessment the analysis includes also two official reports by National Bank of Poland, the country’s central bank, published in 2009 and 2014. The other objective is to note and assess the reforms which have been undertaken by member states of the Eurozone in response to this crisis, in order to maintain and enhance financial stability and economic effectiveness of the rules adopted at the start of the Eurozone on 1 January 1999. The author suggests to consider and adopt additional reforms. Discussed is also the USA experience with its own monetary union, and the potential influence on policy developments in the EU of increasing global competitive pressures from China and India.