Purpose: This study aims to examine the impact of perceived health problems after cancer on perceived physical and mental functioning among adolescent and young adult (AYA) survivors of childhood cancer in Korea. Method: Participants were 225 cancer survivors who were diagnosed before the age of 19, are currently between 15 and 39 years old, and had completed cancer treatment. Each participant completed structured questionnaires. Data were analyzed using descriptive analyses, independent sample t-tests, and multivariate linear regression analyses. Results: A majority (73.1%) of the Korean AYA cancer survivors reported at least one health problem. Growth issues ranked as the most frequently reported; followed by chronic fatigue, vision, learning/memory issues, and weak bones. Those with learning/memory and chronic fatigue issues reported both lower physical and mental functioning. The greater number of health problems the survivors reported was associated with the lower levels of their perceived physical and mental functioning after controlling for age, gender, cancer type, cancer recurrence, and time since diagnosis. Conclusion: Perceived health problems were prevalent among childhood cancer survivors and were significant in assessing physical and mental functioning. Although late effects after treatment for childhood cancer have been well documented internationally, this study is unique in that it helps understand cancer survivors treated in Korea and raises awareness in Korean society. (C) 2013 Elsevier Ltd. All rights reserved.