The evidence that the sponsor of a clinical trial fulfills the obligation to perform oversight of, e.g. a CRO that carries out outsourced study activities on behalf of the sponsor is not new. Nevertheless, the addendum to the ICH-GCP has explicitly included this as a sponsor responsibility under point 5.2.2. It applies to all sponsors of a clinical trial, independent of the kind of the clinical trial, whether commercial or academic study, if the study activities are outsourced to a CRO. The goal is to ensure the patient safety and data integrity. The review of the sponsor's oversight is also subject to e.g. an inspection by an authority. The first edition of this manual is based on a master's thesis within the framework of the university master's program "Clinical Research". The concept developed is certainly not completely new but is based, inter alia. to already discussed measures or publications, as example, by the English authority MHRA. It is intended to serve as an example to illustrate how the sponsor's duty of supervision can be implemented simply and efficiently in rather small, medium-sized companies. Of course, every company has to decide for itself how to implement it.