The analysis of external economic relations of Russia reveals a paradox: while Europe is the main trade and direct investment partner of Russia, this is far from being the case concerning its currency's role in Russian financial sphere. Dollar is largely preferred by economic agents for their financial operations. This paper proposes a disaggregated approach to this issue by separating transactional, financial and precautionary component of the demand for substitution currencies. The influence of three main factors (inertial component, real trade relations and exchange rate fluctuations) on relative demand of euro from Russian economic agents is tested for the period 1999-2004. Finally we suggest a theoretical interpretation of this issue using conventions theory approach.