Document beliefs about the contribution of physical activity to preschool-aged children's health held by Latino mothers in farmworker families, and delineate their perceived barriers or constraints that impose limits on preschool-aged children's physical activity. Qualitative data obtained through semi-structured in-depth interviews (N = 33) with mothers of preschool-aged children living in Latino farmworker families in North Carolina. Mothers universally agree that regular vigorous physical activity is good for preschool-aged children's health, including obesity prevention. However, excessive physical activity can produce illnesses, as well as other physical and emotional problems, and should be limited. Mothers wanted their children to engage in more sedentary forms of activity because they believed it would benefit learning. Physical and chemical hazards in rural environments, distance to parks and play spaces, and lack of familiarity and concerns about neighbors constrained children's physical activity. Although physical activity is believed to be beneficial, strong cultural beliefs and real contextual barriers undermine preschool-aged Latino farmworker children's level of physical activity.