Disenrollment rates have often been used as indicators of health plan quality, because they are readily available and easily understood by purchasers, health plans, and consumers. Over the past few years, however, indicators that more directly measure technical quality and consumer experiences with care have become available. In this observational study, we examined the relationship between voluntary disenrollment rates from Medicare managed care (MMC) plans and other measures of health plan quality. The results demonstrate that voluntary disenrollment rates are strongly related to direct measures of patient experiences with care and are an important complement to other measures of health plan performance.