ABSTRACT The Childhood Cancer Survivor Study (CCSS; U24 CA055727; PI: Armstrong) is a multi-institutional, multi- disciplinary collaborative research resource established to systematically evaluate long-term outcomes among children diagnosed with cancer who survived five or more years from diagnosis. With the successful recruitment and longitudinal follow-up of the cohort that includes survivors diagnosed and treated over three decades (1970- 1999), the CCSS is the world’s largest established open resource for survivorship research with 38,036 eligible survivors available for investigation of late mortality, and 25,665 participants who have contributed health-related and quality of life outcomes. The resource includes comprehensive annotation of treatment exposures, ongoing longitudinal follow-up and an established biorepository from which genotype (single nucleotide polymorphisms [SNP] array) and DNA sequencing of 8,380 survivors are available to investigators for identification of genetic susceptibility for disease- and treatment- related late effects. The objective of the current supplement application is to pilot recruitment of participants from two Children’s Oncology Group (COG) clinical trials for treatment of Hodgkin lymphoma (HL). Results will inform a future expansion of the Childhood Cancer Survivor Study.