This paper provides a rationale for the importance of studying health outcomes in cancer survivors, including their growing numbers, the need for detailed information on the short and long-term effects of treatment, and the interactions of cancer with other comorbid conditions. However, there are a number of challenges associated with this research. Identification and recruitment of cancer survivors is not always easy, and linking their current health status to details of medical treatment is important, but not always feasible. National surveys and databases are a potential source of information on survivors, but may not provide sufficient details for this type of research. Strategies need to be developed to plan for long-term outcome studies in cancer patients from the very beginning of treatment to obtain the most comprehensive data on the outcomes of survivors.