„Axenic“, a GMP certified company filling sterile phials, has repeatedly struggled with a deviation of the process temperature in the filling area. Thus, an internal audit was arranged. This bachelor thesis deals with the planning (creation of an audit plan) as well as the competences and responsibilities involved in this case-specific inspection. Moreover, the carrying out on the basis of a previously developed SOP (standard operating procedure) for internal (and external) audits (as well as inspections and supplier audits) will be discussed in this thesis. For this purpose, an audit log was created. Finally, a closing report of the performed audit indicating shortcomings and drawing conclusions for corrective and preventive actions (CAPA) was compiled.