The German concept of “intercultural opening” is an approach to facilitating migrants’ access to the health care system and improving the care they receive. No data exist concerning the current status of the implementation of this approach in Germany, and the concept has never been analysed in practice. To assess the status of “intercultural opening” in the German mental health care system and to further analyse the concept, we developed a tool by combining pre-existing instruments. In order to review the preliminary tool we combined experts’ knowledge by carrying out a consensusoriented, expert-based Delphi process with actual practice by piloting the instrument in each type of institution to be assessed. The assessment tool thus developed1 is the first one to evaluate the current status of “intercultural opening” in the community mental health care system in Germany from a broad perspective. This paper is intended to present the development process of our assessment tool for demonstrating the benefits of this approach and as a model for future studies, as well as to increase transparency in relation to the current German approach to health care structures in dealing with migrants.