T-cell apoptosis is central to the resolution of chronic inflammation. Inhibition of this process of programmed cell death contributes to disease persistence in conditions such as rheumatoid arthritis. An understanding of T-cell apoptosis and its regulation is clearly important for understanding the pathophysiology of inflammatory disease. This chapter describes a number of apoptosis assays that can be used to measure T-cell apoptosis in synovial fluid. The choice of assay depends, in part, on the phase of apoptosis under investigation and this review puts this into context by introducing these phases and their regulation.