This study describes obesity prevention practices and environments in Head Start, the largest federally funded early childhood education initiative in the United States. Most programs reported doing more to support healthy eating and physical activity than federal performance standards require. Ninety-four percent of the programs studied served some fruit each day, other than 100 percent fruit juice; 97 percent served some vegetables, other than fried potatoes. Fifty-four percent did not allow soda or other vending machines for staff use; 96 percent did not keep children sitting for more than 30 minutes at a time; and 89 percent had an on-site outdoor play area at every center. In addition, more than half (56 percent) provided children with at least 60 minutes each day of unstructured physical activity in addition to the 30 minutes of adult-led physical activity. Data were collected from a self-administered survey included as part of the Study of Healthy Activity and Eating Practices and Environments in Head Start (SHAPES).