Noting that infants should be encouraged to be physically active from the beginning of life to enhance physical and cognitive development, this statement provides teachers, parents, caregivers, and health care professionals with guidelines that address the kinds of activities, the environment, and the individuals responsible for facilitating very young children's physical activity. Following an introduction and overview, the statement provides five guidelines for each age group: infants (birth to 12 months), toddlers (12 to 36 months), and preschoolers (3 to 5 years). Each guideline addresses the "what,""where," and "who" of physical activity. Following the guidelines, the statement answers frequently asked questions. A glossary and chart of common motor behaviors, by age, conclude the statement. (Contains 40 references and lists recommended resources and related Web sites.) (HTH)