Publisher Summary This chapter discusses the possible applications of flow cytometry to kinetic measurements of cell function and describes the general advantages and disadvantages of fluorescent techniques. The flow cytometer is an instrument that was originally designed to examine cell-surface antigens as cell type markers. However, because of its various advantages, it is currently used to perform multiparameter kinetic studies of stimulus responses of suspendable cells and to correlate these parameters for each cell with the receptor occupancy of that cell. This chapter also describes the parameters that can be measured using flow cytometry. Various different classes of fluorescent probes include distributive probes, distributive probe concentration limitations, in situ cytoplasmic probes, intensity of fluorescence as an indicator, ratio of fluorescence as an indicator, and in situ probe concentration limitations. As more probes become available, the number of possible applications of multiparameter flow kinetic techniques will increase. As the ability to design non-interference between the probes increases, the scope of flow cytometry usage will increase tremendously.