This chapter examines two issues: First, it investigates the efficiency of the banking system in six European countries spanning the period of 1994 to 2008. The methodology used is the profit frontier methodology, following the approach suggested in Mester (1996), who indicates that financial capital should be taken into account. Furthermore total assets consist an additional variable that controls for size and is included in the model as well. Second, the chapter examines the impact of efficiency on monetary policy, through the bank lending channel, using the GMM estimator methodology suggested in Arellano and Bond (1991). The results indicate that when efficiency is explicitly included in the model, it weakens the operation of the bank lending channel.