Obesity is rapidly becoming one of the more serious public health challenges of this century, especially when considering that overweight and obese children are likely to stay obese into adulthood and are at a higher risk of developing chronic diseases at a younger age. The need for changes to modifiable risk factors associated with obesity and chronic diseases is paramount. Physical activity is associated with the reduction of several chronic diseases in adults, including breast cancer, colorectal cancer, CVD, stroke, high blood pressure, type 2 diabetes, osteoporosis, and hypertension. In children 5 to 17 years old, physical activity and high physical fitness help guard against high blood pressure, high blood cholesterol, metabolic syndrome, low bone density, depression, injuries, and obesity. Unfortunately in Canada, well over half the adult population, and almost half the child population, are not active enough to reap these health benefits. Children spend considerable time within the care of their parents, and indeed parents appear to be the 'gatekeepers' of children and their experiences during family time. Our review of 34 intergenerational studies showed that parental support was synonymous with physical activity in their children. Thus, focusing on the parent as a means to changing youth physical activity appears a necessity. At present, physical activity interventions focused on the family are limited and have resulted in negligible changes. A recent review of these studies demonstrated very low success in producing behavior change - considerably lower than the comparable adult literature. The authors suggest that focused research attention needs to be placed on the family in order to improve our current practice of physical activity promotion. Our pilot study [15], which serves as the template for this research proposal, demonstrated that focused planning on when, what, how, where, and overcoming other expected barriers followed by prompts and cues resulted in a significant change in physical activity over the more standard persuasion/education approach. The following proposal is an extension of this line of successful research with improvements to the methodological rigor and sample generalizability used in the pilot study.