Background Case study research is a valuable way to explore and describe nursing phenomena in their natural contexts. Multiple sources of evidence are critical in this approach. It is imperative that the strategies for selection, collection and analysis of cases are considered and articulated in the early stages of planning, to avoid having large datasets which cannot be harmonised.Aim To critically examine what is meant by 'multiple sources of evidence' and how they can be used in case study research. Two examples of case study research are used to illustrate the decisions the authors made during the selection, collection and analysis stages of the research.Discussion These decisions included what sources would be used, rationales for their use, and how the data would be collected and analysed. In addition, multiple sources of evidence can result in large amounts of data so the use of NVivo to manage the data is described.Conclusion Each source of evidence selected must have a clear purpose and relate to the study's objectives. Clarification of this during the early planning of any research is imperative.Implications for practice The authors hope that the examples provided to illustrate how multiple sources of evidence are used will guide researchers conducting case study research.