The article addresses the issue of whether or not Poland should join the euro area. Specifically, the author tries to answer three key questions: first, whether Poland has a legal obligation to adopt the euro, second, whether euro adoption is beneficial to the Polish economy, and third, if the answer is “yes,” how and when Poland should join. On the first question, the author demonstrates that Poland has a legal obligation to adopt the euro. This is because European treaties impose this obligation on all new EU member states and this obligation was not challenged by Poland when it negotiated and ratified the EU Accession Treaty. Addressing the second question, the author argues that Poland fulfills the standard optimum currency-area conditions to the extent similar to other euro-area member countries. The author attempts to estimate the main economic costs and benefits of euro adoption. The analysis shows that euro adoption is, on balance, beneficial for Poland, and that annual net benefits, including both static and dynamic effects, could be in the range of 1.5-2.0% of GDP in the longer run. On the third question, the author argues that Poland should not adopt the euro unless several important conditions are met first. Among these are the formal nominal convergence criteria, efficient banking regulations and supervision to avoid credit booms, improved labor market flexibility, and strengthened structural fiscal position. Moreover, euro adoption not only needs much stronger support from Polish citizens, but also requires a change of the Polish constitution, which is a politically challenging task.