The Single Supervisory Mechanism (SSM) is a striking example of the tendency within the EU to transfer decisive, regulatory and enforcement powers to the EU level. The SSM involves a complex system of mixed administration in order to ensure effective banking supervision within the Eurozone. Whereas such mixed administration might be necessary in order to achieve effective cross-border supervision, it also creates legal uncertainties due to the different legal orders involved. In this paper, the effect of the mixed administration on formal and substantive judicial protection is discussed.The paper analyses the right of access to the courts in the case of common procedures and certain ECB decisions. Furthermore, it is examined whether the ECB and national competent authorities have adequate powers to carry out supervision within the SSM. Lastly, the paper pursues the issues with regard to substantive judicial protection in greater depth, in particular the right of respect for the home and the rights of defence.