Any effort to gather evidence may prove pointless without ensuring its admissibility. Despite this fact, the EU still remains silent with regard to the admissibility of evidence collected in the EU cross-border context. The recent instrument developed to ensure the free gathering and use of evidence in the EU, namely the European investigation order, does not refer to the admissibility of evidence collected within this instrument at all. Instead, the EU still believes that the admissibility of evidence may be ensured by the forum regit actum principle, originally developed in the framework of traditional mutual legal assistance. However, the simple copying and pasting of the forum regit actum principle from mutual legal assistance to mutual recognition instruments should be considered as a very unfortunate decision, contradictory to the philosophy of mutual recognition, worsening national standards of evidence gathering, and insufficient in the light of the modern framework for obtaining evidence abroad created by the EIO Directive. Hence, a new and comprehensive common EU approach to evidence gathered in the EU cross-border context proves to be absolutely paramount. This approach should be based on Art. 82.2 (a) TFEU which entitles member states to establish minimum rules concerning, inter alia, the mutual admissibility of evidence between member states. These minimum rules should take into account the differences between the legal traditions and systems across the EU. In the evidentiary field, these standards should enhance mutual trust between member states with regard to the way the evidence has been gathered and the procedural rights associated thereto. Different investigative measures, given their diverse nature and the potential abuses that they may cause, will therefore also require different, measure-specific minimum standards. Accordingly, this research deals with two distinct measures: telephone tapping and house search. The main objective of the study is to find out whether, in view of enhancing mutual admissibility of evidence, it is feasible to come to various types of common EU minimum standards: a) minimum standards to ensure the per se admissibility of evidence – to that end, it is examined whether it is feasible to come to minimum rules for telephone tapping and house search, in particular, - as far as the scope of both measures is concerned ratione auctoritatis, ratione materiae, ratione loci, ratione tempori and ratione personae; and - as far as the procedural rights related with the respective measures are concerned, namely, the right to be notified of them and the right to legal remedies against their taking; b) minimum standards with regard to the admissibility of evidence obtained irregularly, in casu collected through telephone tapping respectively house search, divided into: -‐ common minimum standards on the basis of which it can be decided when irregular evidence, which obviously cannot constitute per se admissible evidence, will be admissible after all (non per se admissibility), and -‐ common minimum standards on the basis of which it can be decided when irregular evidence will be inadmissible in any event (per se inadmissibility). Through a double case study of telephone tapping and house search, this study examines whether the deriving of the standards reported above is feasible and whether complying with these minimum standards would finally shape the so far nonexistent concept of the free movement and mutual recognition of evidence in criminal matters in the EU.