In accordance with the Medical Devices Act, in order to protect patients, medical products have to be subjected to comprehensive tests before they become available on the market. One of these necessary tests is providing proof of biocompatibility. This must be guaranteed independently of whether the medical product is used for a short-term, long-term or even lasting body contact. With our many years of experience, we at the Fraunhofer IGB have established the testing of biocompatibility and cytotoxicity according to DIN EN ISO 10993-5. In order to verify the biocompatibility of materials in vitro, in addition to very wide range of cell lines (DIN EN ISO 10993-5) or primary cells of different tissues, we also employ three-dimensional test systems with organ-specific properties. As one of the first 3D models, we obtained accreditation for our 3D skin model on the basis of DIN EN ISO 10993.