Child obesity is considered a public health problem worldwide. According to the Pan American Health Organization (PAHO), the rates of overweight and obesity have increased disproportionately throughout the world, especially in the Americas, and with greater impact on children. Increase ranges from 11% to 21% from the year 1990 to the year 2000 in child population; in the Americas an increase is observed, with a rise of 24% in Mexico, 14% in Chile and 12% in Peru. In accord to PAHO data and the World Health Organization, this obesity is related to risk factors that are inducers which can generate obesity. Purpose: Determine the effectiveness of prescription of physical activity in overweight and obese child population according to the levels of evidence through a systematic revision in randomized controlled clinical trials in children under 16 of the physical activity programs, considering as result variables body mass index (BMI), BMI Z score and % fat