Abstract This study evaluates the dynamics between the dollar and euro balances in the Estonian economy. The focus is to apply the traditional currency substitution model to the substitution of the substitute currency, the dollar and euro-related foreign currency balances. We find substitution between the dollar and the euro to be asymmetric in the short run. Inertia, irreversibility and ratchet effects favoured the use of the euro as a substitute currency. No significant evidence of asymmetries in the long run was detected. However, in general, a traditional model for currency substitution was capable of explaining the dynamics of the euro and the dollar as substitute foreign currencies.