Abstract The aim of this chapter is to consider the nature of process evaluation methodology in health services research, with a particular focus on palliative and end-of-life care research. The development of process evaluation methodology is examined, including the influence of the Medical Research Council’s guidance on the evaluation of complex health interventions. A key feature of the chapter is the identification of common components of process evaluations, based on examination of studies conducted in palliative and end-of-life care. Having identified these components, recommendations for conducting process evaluations in these areas are made. The chapter concludes that process evaluations are an essential tool for researchers working in this area, but that there is scope for a more explicit approach to implementing and reporting these studies.