The United States has seen major advances in medical care during the past decades, but access to care at an affordable cost is not universal. Many Americans lack health care insurance of any kind, and many others with insurance are nonetheless exposed to financial risk because of high premiums, deductibles, co-pays, limits on insurance payments, and uncovered services. One might expect that the U.S. poverty measure would capture these financial effects and trends in them over time. Yet the current official poverty measure developed in the early 1960s does not take into account significant increases and variations in medical care costs, insurance coverage, out-of-pocket spending, and the financial burden imposed on families and individuals. Although medical costs consume a growing share of family and national income and studies regularly document high rates of medical financial stress and debt, the current poverty measure does not capture the consequences for families' economic security or their income available for other basic needs.