OBJECTIVE: To describe obesity prevention practices and environments in Head Start, the largest federally funded early childhood education program in the United States. DESIGN: Self-administered survey as part of the Study of Healthy Activity and Eating Practices and Environments in Head Start (SHAPES).  SETTING: Head Start, 2008. PARTICIPANTS: Directors of all 1810 Head Start programs, excluding those in US territories. OUTCOME MEASURES: Descriptive measures of reported practices and environments related to healthy eating and gross motor activity. RESULTS: The 1583 (87%) programs responding to the survey enrolled 828 707 preschool children. Of these programs, 70% reported serving only nonfat or 1% fat milk. Ninety-four percent of programs reported that each day they served children some fruit other than 100% fruit juice; 97% reported serving some vegetable other than fried potatoes; and 91% reported both of these daily practices. Sixty-six percent of programs said they celebrated special events with healthy foods or nonfood treats, and 54% did not allow vending machines for staff. Having an on-site outdoor play area at every center was reported by 89% of programs. Seventy-four percent of programs reported that children were given structured (adult-led or -guided) gross motor activity for at least 30 minutes each day; 73% reported that children were given unstructured gross motor activity for at least 30 minutes each day, and 56% reported both of these daily practices. CONCLUSION: Most Head Start programs report doing more to support healthy eating and gross motor activity than required by federal performance standards in these areas.