The Veterans Health Study (VHS) followed a cohort of patients receiving ambulatory care in the Veterans Affairs healthcare system for up to 5 years. One of the principal aims of this study was to develop a library of methodologies including general and disease-specific health outcome questionnaires for use in monitoring the quality of healthcare and for research purposes. The cornerstone for this work is the Veterans RAND 36 and 12 Item Health Surveys (VR-36 and VR-12), a general measure developed in the VHS for measuring the physical and psychologic well-being of the patient. A comprehensive set of disease-specific assessments has also been developed as part of this study for the purposes of monitoring specific chronic conditions more commonly seen in routine ambulatory care settings. Since 1996, more than 2 million questionnaires have been administered in the VA for quality monitoring purposes, using the VR-36 and VR-12. Research studies that have used these batteries span randomized clinical trials in the VA cooperative studies program and clinical effectiveness research. Health assessments using VHS batteries are being disseminated for widespread use outside the VA. Chief among the assessments used is the VR-12, which has recently been included in the 2006 Health Plan Employer Data and Information Set (HEDIS) as part of the Medicare Health Outcomes Survey for monitoring the Medicare Advantage Program. The methods and batteries developed in the VHS are in the public domain and provide a framework for future patient monitoring using standard measures of health.