Quality defects are a common problem for producing companies, but causes and consequences are often unknown. The purpose of this thesis assignment is to develop a step-by-step analysis method for identifying the root causes of quality defects based on previously examined consequences. The first steps focus on customer recovery meanwhile the following steps concentrate on process recovery. The analysis method is process-orientated as the complete production and delivery process are scrutinized upstream by the combination of commonly used quality tools.   For testing the applicability of the presented method this thesis comprises a case study conducted at one company receiving complaints about quality defects. For the Case Study Company the consequences and causes of quality defects are described, analyzed and suggestions for improvement are developed.   In the investigated case, the developed method helps to identify causes and consequences of incomplete delivery, the company’s major quality problem. The upstream approach proved advantages for two reasons. First of all including the customer side guarantees that the cause analysis is limited to the relevant problems. With the help of the method the severity of consequences depending on the customers’ awareness of defects and available time can be detected. Secondly problems can be scrutinized in natural order as difficulties in production once identified can be followed step by step to the causes in a preceding step. The main causes identified in this case study are a lack of process definition and of standardization. Thus, the portrayed case suggests that regular appearances of quality defects are not a coincidence. The reasons are the underlying, possibly insufficiently defined and managed processes.   The general finding of the thesis assignment is the presented analysis method that comprises a systematic process-oriented approach designed to examine consequences and causes of quality defects. In contrast to the root cause analysis approaches found in literature each analysis step is described in detail. This makes the method easy to apply in practice. Therefore the method is a valid tool to deal with a high degree of complexity. The case study proved that it is effective and efficient to scrutinize problems with these characteristics. Under different circumstances the application of single quality tools might be sufficient and hence resource effective. Further investigation is necessary since this method has only been tested in one case study.