The Veterans Health Administration (VA) is the nation's largest public integrated health care system and the largest single provider of health care to HIV-positive patients in the United States. First established in 1992, the Immunology Case Registry (ICR) is a national-level administrative database originally designed to monitor health care service utilization. With its interface to the VA electronic medical record, the ICR provides an opportunity to monitor and improve the quality of clinical care for HIV-positive patients receiving VA care. To realize this potential, key data element enhancements and quality review systems are being put into place. A brief description of the population included in the ICR is provided, along with current data limitations and planned improvements for data collection. The ICR, now managed by a national quality management center, is being updated and systematically improved for local clinical use. As local data capture improves, the ICR will prove to be an invaluable resource for assessing the quality of HIV care in the VA system and patient outcomes from that care.n. (C) 2001 Elsevier Science Inc. All rights reserved.