The National Cancer Institute-supported Childhood Cancer Survivor Study (CCSS) is a cohort of approximately 20,000 survivors and approximately 4,000 siblings of survivors of pediatric cancers diagnosed between 1970 and 1986. A recently initiated expansion of the study aims to enroll an equally large cohort of survivors diagnosed between 1987 and 1999. Investigators can use CCSS funds to conduct analyses of the data collected through the cohort study, as well as to use outside funds for research making use of the cohort. NCI is considering conducting an evaluation of the CCSS, and tasked STPI to conduct a preliminary Feasibility Study. The purpose of this Feasibility Study was to explore whether evaluation of the CCSS is both warranted and feasible, and, if so, to make recommendations regarding the design of such an evaluation. The Feasibility Study team found that most CCSS outcomes are clearly defined and measurable. Further, no extraordinary barriers to additional data collection are anticipated and existing databases can be used as complementary data sources. An Outcome Evaluation of the CCSS would therefore be feasible. However, such an evaluation is not warranted, especially because such a study would not help the National Cancer Institute address the critical strategic issues it faces with respect to the future of its pediatric cancer survivorship research portfolio.