This chapter highlights the potential of a longitudinal approach to gain better insight into the dynamic patterns of working poverty. While cross-sectional research can show us the characteristics of people at risk of in-work poverty, it cannot show us how transitory or persistent in-work poverty is. A longitudinal approach can further our insight by showing the duration of in-work poverty, the typical sequence of events leading to working poverty and the patterns of exit from in-work poverty. It can furthermore show us which population groups are at risk of persistent working poverty, and how episodes of working poverty are embedded in the life course. We start this chapter with highlighting the advantages of a longitudinal approach to working poverty. In a second section we will review the existing research evidence on dynamic approaches to poverty and employment. In the third section we will introduce the research design needed to study dynamics of working poverty. This includes a discussion of the type of data necessary (socio-economic household panel data), as well as a brief overview of the relevant analysis techniques. The fourth section of the chapter includes empirical examples of the dynamics of in-work poverty.