The Comprehensive Sexual Assault Assessment Tool (CSAAT) was developed for collection of data about the victims and offenders in cases of rape and sexual assault. The CSAAT provides a systematic guide for victim assessment, evidence documentation, and initial treatment.Use of the CSAAT facilitates collection of investigative data about the victim and the offender that are critical components of victim interviews and crime investigations, as well as victim forensic data. The CSAAT can be used by health care professionals who care for the victims of sexual assault. The tool reflects the major concepts of the Roy Adaptation Model and was designed as a victim evaluation report for clinical and forensic purposes. The CSAAT can also be used to compile agency statistics, as part of the training for sexual assault nurse examiners, and to collect research data. A case study involving two victims illustrates the importance of evidence collection and use of the Federal Bureau of Investigation's Combined DNA Index System (CODIS) for linking victims by offender DNA.