The information can be used to determine eligibility for a drug treatment program or research project and to route clients to services that best suit their needs. In addition, intake data can be used to establish a baseline description of clients for treatment planning and review or of the treatment population for program accountability and evaluation. Several instruments have been developed to document the psychosocial characteristics of clients. One of the most widely used instruments, the Addiction Severity Index (ASI), uses a minimum set of items across repeated assessments to provide information for clinical treatment planning and treatment evaluation. The most recent edition of the ASI includes new items about important life outcomes, such as physical and sexual abuse and long-term personal relationships. The rationale for and context of developing the psychosocial history to supplement the ASI and other instruments to document the psychosocial characteristics of clients are addressed, and steps in developing the psychosocial history are detailed. Implementation of the psychosocial history at a family center offering comprehensive medical and psychosocial services for pregnant and parenting drug-dependent women and their children is described. The authors conclude the psychosocial history can serve both clinical and research purposes. Illustrations of selected psychosocial history data are provided, and excerpts from a psychosocial history form are appended. 29 references