Physical activity may improve quality of life, the control of comorbid conditions, and weight management while reducing breast cancer recurrence and mortality among breast cancer survivors. Unfortunately, most breast cancer survivors do not engage in regular physical activity. In fact, breast cancer survivors are often less active after a diagnosis and may not return to pre-diagnosis activity levels. Therefore, we conducted a pilot study, "BEAT Cancer", to test a specifically defined physical activity behavior change intervention to increase physical activity for breast cancer survivors. The pilot study showed significant improvement in both physical activity and health outcomes for the study participants after the intervention. Importantly, the pilot intervention resulted in changes in physical activity and social cognitive theory constructs, such as the participants feeling more confident in their ability to exercise. The positive results enhance our potential for testing mechanisms that encourage physical activity behavior change in breast cancer survivors. The current study is a follow-up to confirm program effectiveness at 3 months and to test sustainability of results at 3-12 months. We propose a multi-center, randomized controlled trial enrolling 356 breast cancer survivors with the following study aims: