Many state Medicaid programs are implementing cost-saving mechanisms, but little is known about the impact of those strategies on low-income people. Recent increases in cost sharing for Oregon Health Plan (OHP, Oregon’s Medicaid program) members have created a natural experiment that is ideal for examining such impacts. Early results from an ongoing cohort study suggest that cost-sharing increases led to a large reduction in OHP membership. Those who left OHP because of the cost-sharing increase reported inferior access to needed care, used primary care less often, and used hospital emergency rooms more often than those who left OHP for other reasons.