The Housing Choice Voucher program plays a critical role in our nation's housing policy. One of its greatest strengths is that it allows families to choose the type of housing and neighborhood that best meets their needs. Social science research clearly shows that living in a distressed, high-poverty neighborhood undermines the well-being of families and the long-term life chances of children. When families are able to move to healthier communities, their lives improve measurably. The proposed State and Local Housing Flexibility Act of 2005 threatens to restrict choice and mobility for voucher families. The current voucher program certainly does not work perfectly, and growing experience points to promising strategies for addressing its weaknesses.