In line with the growing EU interest in cross-border gathering and use of evidence in criminal matters, the European Commission confirmed its intention to review the entirety of the current mutual legal assistance framework with a view to introduce more mutual recognition-like features therein. In practice this can lead to the obligation to recognize per se admissibility of foreign evidence in the course of new criminal proceedings, if such evidence is admissible according to the law of the member state that gathered the evidence. When attempting such an introduction of mutual recognition-like features into the cross-border gathering and use of evidence in criminal matters, specific types of evidence deserve a special focus. Scientific expert evidence in criminal matters is one of those special types of evidence. At member state level, a wide variety exists in the regulations concerning appointing and remunerating scientific experts, the criteria for expertise, reliability and independence of experts and in the admissibility and value of the produced evidence. Because of this debate at national level, significant distrust between member states is more than likely. This article links in with these recent developments. Mutual recognition of expert evidence can only be acceptable if a thorough reflection on the differences between national regulations and practices is followed by setting up EU level minimum rules and quality standards.