Apoptosis, or programmed cell death, is an important physiologic process multicellular organisms use to maintain homeostasis by providing a means for elimination of redundant cells during development. Furthermore, cells that have become damaged or are defective undergo apoptosis to prevent disease. It is an important process involved in the etiology, pathogenesis, and response to therapy of a variety of diseases. Specific biochemical changes occur in cell or tissue undergoing apoptosis that offer potential targets for imaging tracers. There are a number of tracers that can be used to identify apoptotic cells, including morphological changes, caspase activation, and DNA fragmentation. In this article, the recent progresses of small molecular based probes for detecting apoptotic cells are reviewed. In addition, the traditional and modern imaging technologies which use to visualize these probes is also discussed.