Health plan "report cards," that is, published summaries of health plan performance, are a new way to help consumers select a health plan on the basis of cost and quality. The Health Plan Employer Data and Information Set (HEDIS) includes a set of health plan performance measures, standardized definitions, and methods for data collection. HEDIS is used as the basis for many report card initiatives and is the preferred tool of the managed care industry for measuring health plan performance. Nevertheless, the current list of HEDIS performance measures omits many health services, including medical nutrition therapy. Nutrition measures have the potential for wide appeal among health care stakeholders (ie, payers, consumers, and providers). Four measures related to medical nutrition therapy are proposed for managed care report cards: staffing for nutrition services and medical nutrition therapy for high cholesterol level, gestational diabetes, and cardiovascular disease. Barriers to adopting medical nutrition therapy measures in HEDIS include the need to address technical issues before considering new measures and competition from other potential measures. Steps to create support for medical nutrition therapy measures in HEDIS should focus on influencing representatives of health plans and employers to include these measures. The involvement of registered dietitians in the dynamic process of health plan evaluation is an important extension of ongoing efforts for strategic positioning in the managed care market.