The 4-H youth development program of the nation's 109 land-grant universities and the Cooperative Extension System is one of the largest youth development organization in the United States serving approximately six million youth. The 4-H Healthy Living initiative began in 2008 to promote achievement of optimal physical, social, and emotional well-being for youth and families. In 2013, the National 4-H Council sought to identify 4-H Healthy Living programs in the domains of healthy eating and physical activity that adhered to the national 4-H Healthy Living mission and were ready for comprehensive outcome evaluation or replication at a national level. This chapter shares findings from an environmental scan of 4-H programs and (a) identifies programs with evidence of promoting a healthy diet and physical activity, (b) describes program impacts related to healthy diet and physical activity, and (c) clarifies select program characteristics associated with reported healthy eating and/or physical activity outcomes. The RE-AIM evaluation framework is introduced as an effective approach to assessing program impact for 4-H Healthy Living and similar out-of-school time programs.