Promoting physical activity in children is an important front battling Childhood obesity. This paper investigates if and by how much neighborhood parks and playgrounds, one of the most important activity-enhancing neighborhood facilities, affect childhood obesity. We employ a covariate matching technique to analyze the 2007 National Survey of Children Health data. We find that neighborhood parks and playgrounds make children more fit. The reduction in body mass index (BMI) as well as the overweight or obesity risk is both statistically and economically significant. We also find that the park impact depends on gender, age, race, income, neighborhood safety, and other neighborhood amenities. The results suggest that a provision of neighborhood parks and playgrounds is likely to make children more fit, but relevant interventions need to take socioeconomic status of the targeted children population as well as other neighborhood amenities into consideration.