This article presents an analysis of economic implications of the major EU enlargement in 2004. The research is based on sigma (σ) and beta (β) convergence of per capita GDP among the 10 countries which joined the European Union in 2004. Our results confirm the existence of both types of convergence in the second half of the 1990s and the 2000s. Generally, the poorer new EU member states grew faster than the richer new EU member states. As a result, the income gap between these two groups of countries has narrowed although it still remains quite large. The convergence occurred at the rate of 4.2% during the period 1992-2006 and 7.0% and 9.6% during the sub-periods 1995-2006 and 2002-06 respectively.