The techniques presented in this chapter describe the experimental procedure for the identification of the nonrandom DNA fragmentation associated with apoptosis. The major benefits of this method are its ability to detect a low level of DNA fragmentation and its ability to detect large DNA fragments (50 kb and 300-1000 kb) as opposed to the internucleosomal DNA ladder. It is a qualitative technique although it can be of limited quantitative value. It can be used to detect apoptosis in cell lines following exposure to a wide variety of agents.