BACKGROUND: Cancer survivors are at increased risk for secondary cancers and other diseases. Healthy dietary practices may improve cancer survivors' health and well-being. OBJECTIVE: The durability of the effects of the FRESH START intervention, a program of sequentially tailored mailed materials, and standardized mailed materials (for controls) on cancer survivors' dietary outcomes was assessed over a 2-year period. Greater dietary gains were expected for FRESH START participants relative to controls. DESIGN: Participants were randomized to receive tailored vs standardized 10-month mailed print interventions promoting diet and exercise behaviors. Data were collected at baseline and 1- and 2-year follow-ups. PARTICIPANTS/SETTING: Breast and prostate cancer survivors (n=543) were recruited from 39 states and two provinces within North America. A total of 489 participants completed the 2-year follow-up assessment (10% attrition). INTERVENTION: Participants were randomly assigned to either a 10-month program of tailored mailed print materials promoting fruit and vegetable consumption, reduced total and saturated fat intake, and/or increased exercise or to a 10-month program of publicly available mailed materials on diet and exercise. MAIN OUTCOME MEASURES: Telephone surveys (supported with blood biomarkers) assessed dietary habits at baseline and 1- and 2-year follow-ups. STATISTICAL ANALYSES PERFORMED: Paired-samples t tests were conducted to examine the durability of the intervention's effects on dietary outcomes within each study arm. Arm differences in follow-up outcomes were then tested with the general linear model, controlling for the baseline value of the outcomes. RESULTS: Both arms reported decreased saturated fat intake, increased servings of fruits and vegetables, and better overall diet quality at year 2 relative to baseline. However, FRESH START participants reported better overall diet quality and lower total and saturated fat intake compared to controls at the 2-year follow-up. CONCLUSIONS: Results suggest that mailed material interventions, especially those that are tailored, can produce long-term dietary improvement among cancer survivors.