Introduction Psychosocial outcomes derived from standardized and disease-specific measures are often used in pediatric oncology; however, the reliability, validity and utility of these instruments in adult survivors of childhood cancer have yet to be established. Purpose To develop and evaluate a new instrument that measures aspects of long-term survivorship not measured by existing tools. Methods A new candidate instrument-the Impact of Cancer for childhood cancer survivors (IOC-CS)-was administered to childhood cancer survivors aged 18-39 who were 21 years of age or younger when diagnosed with cancer. Psychometric properties of newly derived scales were assessed. Results Factor analyses of items derived eight new and specific subscales: Life Challenges, Body/Health, Talking With Parents, Personal Growth, Thinking/Memory Problems, Health Literacy, Socializing and Financial Problems. Internal consistency measurements for these subscales ranged from 0.70 to 0.86. Expected associations within and among the IOC-CS subscales and standardized measures of health-related quality of life (HRQOL) were observed, as were some unexpected findings. Conclusion Psychometric analyses indicated that this initial version of the IOC-CS measures distinct and relevant constructs for young adult survivors of childhood cancer. Future work is necessary to confirm the responsiveness and further validate the instrument in multiple and representative samples.