Postoperative pain is the expected but nonetheless undesirable byproduct of all surgical procedures. Humanitarian concerns and recent quasi-governmental regulations have heightened awareness about the importance of treating postoperative pain. This guideline builds upon the foundation created by the Agency for Health Care Policy and Research guideline published in 1993, highlights changes that have occurred over the past 10 years, and makes recommendations based on the current scientific evidence. In addition, it takes advantage of the versatile information management inherent in a web-based format to make the information readily available.A multidisciplinary group of physicians, dentists, nurses, pharmacists, physical therapists, psychologists, and ethicists from the Veterans Health Administration (VHA) and Department of Defense (DoD) in conjunction with the VHA Office of Quality and Performance and a consultant group developed a postoperative pain algorithm and supporting documentation. The guideline structure and content were determined by a standardized rating of the evidence gleaned from comprehensive electronic searches.An interactive electronic and traditional "paper" guideline with a pre- and postoperative algorithm was developed. A table, which provides a menu of analgesic choices organized by specific operation, was constructed. Preferences for particular analgesic techniques and classes of medications were identified. A postoperative pain interactive pharmacopoeia and printable patient educational materials were also provided. The guideline may be reviewed at the following website: www.oqp.med.va.gov/cpg/cpg.htm.This postoperative pain guideline provides readily accessible information and evidence-based guidance to a variety of providers. It highlights deficiencies in our understanding of the pain and recovery processes and how they might guide our choices of postoperative analgesic techniques. In combination with the powerful system-wide data collection capabilities of the VHA, there may be improved understanding of what techniques are useful. Finally, it may lead to the development of reliable, individualized analgesic plans for specific surgical procedures that incorporate the full range of pharmacologic and nonpharmacologic techniques.