Obesity and a sedentary lifestyle are highly prevalent in cancer survivors, and a growing number of publications have shown statistically and clinically significant associations between low levels of physical activity, obesity and cancer recurrence and death. Adoption and maintenance of physical activity is a difficult challenge for healthy adults, and is likely to be even more difficult after a cancer diagnosis. More effective strategies to increase physical activity in cancer survivors should be explored. The purpose of this paper is to (1) provide a rationale for physical activity interventions and programmes for cancer survivors, and (2) discuss successful approaches to adopting and maintaining physical activity to meet evidence based recommendations and ultimately improve cancer survival and overall survival. Since a majority of cancer survivors are not currently participating in recommended levels of physical activity, resulting in greater disease risk and health care costs, targeted exercise therapy has the potential to benefit a large number of cancer survivors. Cancer survivors should seek out the opportunities that exist towards being physically active, and oncologists should also become aware of the benefits of exercise, assist their patients by endorsing existing physical activity guidelines, and refer their patients to certified cancer exercise trainers.