This paper analyses the synchronization of business cycles between new and old EU members using various measures. The main findings are that Hungary, Poland and Slovenia have achieved a high degree of synchronization for GDP, industry and exports, but not for consumption and services. The other CEECs have achieved less or no synchronization. There has been significant increase in synchronization of GDP and its major components within EMU. This lends support to the argument of OCA endogeneity but there is also evidence of a world cycle. The consumption-correlation puzzle remains, but its magnitude has greatly diminished in the EMU members.