In compliance with Section 724 of the Stewart B. McKinney Homeless Assistance Act of July 22, 1987 (Public Law 100-77), this GAO report to Congressional Committees provides estimates of the number of homeless children and youth in all states. Estimates are reported, along with additional information on subgroups for whom it was not possible to obtain unduplicated counts. Findings indicate that on a given night, about 68,000 children and youth of 16 and younger may be members of families that are literally homeless. Of these children and youth, about 25,500 are likely to be in urban shelters and hotels; about 21,800 in suburban and rural areas; about 4,000 in churches; about 9,000 in abandoned buildings, cars, or public places; and about 7,700 in various other settings. In addition to children and youth who are literally homeless, nearly 186,000 may be precariously housed in shared housing. These estimates do not include homeless runaway children and youth. Appendices include a review of objective, scope, and methodology; estimates of the number of homeless children and youth; characteristics of children and youth in urban shelters; homeless children and youth not included in the estimates; the number of families served annually; methods of comparison with other estimates; experts consulted; and major contributors to the report. (RH)