Through the Child Care and Development Fund (CCDF), the U.S. Department of Health and Human Services (HHS) subsidizes child care for low-income families whose parents work or attend education or training programs. In fiscal year 2009, the CCDF budget was $7 billion. States are responsible for determining program priorities and overseeing funds. Providers--who range from child care centers to relatives--bill the state for caring for approved children. Unregulated relatives represent 12 percent of providers in the CCDF program. In response to program fraud and abuse, GAO (1) proactively tested selected states' fraud prevention controls, (2) examined closed case studies of fraud and abuse, and (3) interviewed parents waitlisted for child care about the effect of this lack of assistance on their families. To do this, GAO investigators posed as parents and unregulated relative providers in 10 scenarios in five states with no waiting lists that each received more than $100 million in CCDF funding for fiscal year 2009. These states did not require fingerprint criminal history checks or site visits. For case studies of past program fraud, GAO reviewed criminal court records and interviewed agency officials. GAO spoke with parents on waiting lists in six states for their perspectives on the effect of being unable to obtain childcare. Results cannot be projected beyond these states or unregulated relative providers. Appended are: (1) Scope and Methodology; and (2) GAO Contact and Staff Acknowledgments. (Contains 5 tables and 38 footnotes.)