Apoptosis is a programmed cell death which can be triggered off by cells in response to variuos physiological and pathological stimuli. Recently;studies on apoptosis of tumour cells have attracted much attention.Some methods to detect apoptotic cells have been developed on bases of the typical morphological and biochemical changes during apoptosis.The application of flow cytometry(FCM)in the study of cell apoptosis. especially the value of some new methods based on FCM is described in detail.