The initial stages of physical evidence examination are pivotal to the successful resolution of criminal investigations. Recent cases clearly reinforce the notion that methods of evidence collection and preservation will continue to be rigorously scrutinized and challenged in court. This article reviews forensic applications of DNA typing, focusing on the collection and preservation of biological evidence. Topics addressed include physical evidence collection at the crime scene, the forensic laboratory, and the autopsy room. Specific concerns pertaining to different sources of DNA evidence are discussed, as are special collection methods associated with various substrates on which the evidence is deposited.