The aim of this article is to enhance the understanding about case studies as one of the research methods used in qualitative research especially in the research field of supply management. By using an example case study this article illustrates how a case study can be conducted successfully and how the validity and reliability of the research should be evaluated. The study shows that a case study as a research method is suitable for the research of supply chain management and purchasing and supply management. Because case study enables the collection of rich and profound data, an in-depth analysis of the phenomenon in question can be reached which can be highly critical for example in the development of supply relationships. The article has practical relevance especially for academic researchers in the fields of supply chain management, logistics, supply management and operations management by offering initial insights into the importance of the research process in case studies. Case studies have been criticized for the lack of rigor and thus it is important to highlight the significance of the accuracy and systematic way of action in the case research.