Although elementary schools have firmly institutionalized programs for children aged 5 and older, the United States is still developing operating public definitions for programs for children below age 5. These programs include public school prekindergarten programs, Head Start programs, and child care homes and centers. This article estimates the per-child and aggregate costs of providing good programs to the populations of young children who need them, specifically: (a) full public funding for part-time programs for 3- and 4-year-olds in poverty with parents who are not in the labor force; (b) full public funding for full-time programs for children under 5 in poverty with employed parents; and (c) both public and private funding for full-time programs for non-poor children under5 whose parents are employed. The article does not estimate program costs for non-poor families of children under 5 whose parents are not employed. It appears that the United States now spends only half of the public and private d...