In Europe, national legal frameworks frequently enable research access to official statistical data, also including detailed microdata, but crosscountry research remains difficult. Accreditation is a central element of the framework for access to data that currently is understood to be a barrier especially for trans-national access. To better understand the nature and causes of the problem, and to devise potential solutions, we have mapped current arrangements across European countries. We identify similarities and differences as well as major gaps and inconsistencies across countries, and we single out best practices and new, example-setting solutions. Overall, our key results are encouraging: almost all European countries do provide research access to their microdata, and most of them allow non-national European researchers to access their data, though under varying conditions. Some of the gaps that we have identified are relatively easy to fill, notably a widespread lack of online information, and unsystematic translation into other languages. A small set of issues, however, will require negotiation and coordination at higher, policy-making levels: the controversial need for institutional accreditation, homogeneization of terminology, and the possibility to introduce special provisions to facilitate trans-national access. Some of these issues are under discussion today and some new solutions are being tested or piloted, so that substantial improvements can be expected in the future.