Using data from the 2008 Survey of Income and Program Participation, we find that information about past income and employment that is available to state Medicaid programs can potentially verify (a) initial financial eligibility for between 55 and 79 percent of eligible applicants and (b) renewed eligibility for between 60 and 71 percent of eligible enrollees. Verifying eligibility based on data matches, rather than documentation from consumers, could lower administrative costs; cut paperwork burdens for consumers, thereby increasing participation levels among those who qualify for help; and prevent eligibility errors.