Background: Survivors of childhood cancer are at increased risk for early development of CHCs, including metabolic syndrome (MetS), low bone mineral density (LBMD), and gastrointestinal (GI) disease. Dietary modification is often recommended for prevention and/or treatment of these CHCs in non-cancer populations. However, associations between diet quality and severity of CHCs in adult survivors of childhood cancer are not well known. Methods: Adult survivors (≥10 years post-diagnosis) of childhood cancer who completed a clinical evaluation and Block Food Frequency Questionnaire were included. Diet quality was estimated using the Mediterranean diet score (aMED), with scores ranging from 0 to 9 (increased scores represent higher adherence to diet). CHCs were graded (modified CTCAE) and classified as “low” (grade ≤1 for LBMD and GI; grade ≤2 for MetS) or “high” (grade 2-4 for LBMD and GI; grade 3-4 for MetS). A multivariable linear regression model was used to estimate the mean aMED score by “low” or “high” disease category, with adjustment for age at evaluation, sex, race, education, total energy intake, adjusted BMI, physical activity, smoking, and alcohol consumption. Results: 2,822 survivors of childhood cancer (52.4% male, 83.1% non-Hispanic white) were included. The most prevalent diagnosis was acute lymphoblastic leukemia (34.1%). Time from primary diagnosis was 24.2±8.5 years and age at recruitment was 32.5±8.7 years. Lower adherence to aMED diet was associated with “high” MetS and LBMD, but not GI disease. See the Table for aMED multivariate-adjusted diet quality scores by CHC. Conclusions: In this cross-sectional analysis, MetS and LBMD were associated with poor adherence to the aMED diet. Although longitudinal investigation of associations between diet quality and CHCs in survivors of childhood cancer are needed to determine causal association between diet quality and CHCs in childhood cancer survivors, dietary interventions in early or late cancer survivors may help prevent development or progression of specific treatment related chronic conditions.