To what extent does the availability of credit depend on monetary policy? And, does this relationship vary with bank characteristics? Based on a common source of balance sheet data for the four largest economies of the eurozone over the period 1999–2011, we find that the effects of monetary policy on bank lending are significant and heterogeneous in Germany and Italy – which are characterized by a large number of banks – but are weaker and more homogeneous in Spain and France – whose banking industry has a higher degree of market concentration. In particular, monetary policy appears to exert larger effects on cooperative and savings banks with lower liquidity and lesser capital in Germany and savings banks with smaller size in Italy. Our results highlight that the transmission of monetary policy over bank lending in the eurozone is highly heterogeneous. From a policy perspective, the increased large number of cooperative and savings banks, which have had access during the last financial crisis to the refinancing operations of the European Central Bank, bodes well for the improvement of the monetary transmission mechanism. The analysis also suggests that competition policy measures aiming at reducing entry barrier might facilitate the transmission mechanism. — Roberto A. De Santis and Paolo Surico