This paper assesses the exchange rate development and the volatility in six new EU member states during the period November 1996 - April 2006. The development is examined by the calculating various rates of return. The exchange rate volatility is analyzed by using the moving average standard deviations of the annualized daily returns of the nominal bilateral exchange rates. The three ERM II participating currencies (SIT, CYP, SKK) entered into the mechanism at the optimal time of stable exchange rate development and low volatility. However, the admissible fluctuation band ±2.25% seems to be too narrow for the remaining three currencies (CZK, HUF, PLN). Thus, these currencies should remain out of ERM II for some time.