Dramatic improvements in the diagnosis and treatment of cancer in childhood have led to a rapidly growing cohort of survivors, now estimated to exceed 420,000. However, this success is associated with the recognition that childhood cancer survivors have significantly elevated risk of premature mortality and serious morbidity related to chronic health conditions that develop at a young age. We have shown that childhood cancer survivors not only have significantly higher body mass index than their peers, they also experience unhealthy weight gain early in treatment and increases in weight are maintained throughout treatment and beyond. Nutrition is one of the cornerstones for cancer prevention and control. Our study using repeated 24 hour diet recalls found that childhood cancer survivors had poor adherence to dietary guidelines. They are particularly burdened by suboptimal intake of whole grains, sodium, and empty calories. In addition, we identified low levels of habitual energy expenditure in childhood cancer survivors. An energy deficit of approximately 500 kcal per day suggests that weight management needs to target both dietary intake and physical activity to achieve energy balance. Intake patterns in childhood cancer survivors are established risk factors for chronic diseases. Our findings highlight the need for ongoing evaluation with childhood survivors to assess intake patterns and targeted intervention to promote healthy consumption to prevent long-term morbidity. Future interventions need to capture sensitive windows for weight gain, and also address changes in parenting styles and specific barriers experienced by survivors and families for healthy eating and active living.