The aim of the article is to compare geographic labor mobility (the migration channel of adjustment) in the eurozone and the USA since the 1990s. The first part of the article contains a review of selected literature on migration in Europe and the USA. In the second part three hypotheses are formulated on the basis of this review. The third part of the article presents the methodology and data used to verify these hypotheses. Tat methodology rests on analyzing how net emigration rates in the period 1992-2011 in eurozone countries and various states in the United States (plus the District of Columbia) reacted to unemployment rates. The fourth part of the article presents the results of the analysis, together with an explanation of the intensity and dynamics of the migration channel of adjustment in both monetary unions. The analysis confirms that migration has been less supportive for the functioning of the monetary union in the eurozone than in the USA. It also shows that visible strengthening of the migration channel in the eurozone seems to have taken place only after 2004, which suggests an association with the European Union enlargement in 2004. For the eurozone, the analysis does not provide convincing evidence that the migration channel strengthened after the outbreak of the fnancial crisis. For the USA the analysis suggests that the fnancial and economic crisis significantly weakened the migration channel. The article ends with concluding remarks.