Given the recent emphasis on the totality of the diet by national guidelines, we examined the relationship between the quality of diet and overall and cancer-specific mortality among cancer survivors. From the Third National Health and Nutrition Examination Survey (NHANES III), 1191 participants diagnosed with cancer were identified. Healthy Eating Index (HEI) scores were utilized; higher HEI score indicated better adherence to dietary recommendations. During a median follow-up of 17.2 years, a total of 607 cancer-specific deaths occurred. A high-quality diet (highest-quartile HEI score) was associated with decreased risk of overall (hazard ratio [HR] = 0.59, 95% confidence interval [CI] = 0.45 to 0.77) and cancer-specific (HR = 0.35, 95% CI = 0.19 to 0.63) mortality when compared with a poor-quality diet (lowest-quartile HEI score). Among individual dietary components, the highest-quartile score for saturated fat intake was associated decreased cancer-specific mortality (HR = 0.55, 95% CI = 0.36 to 0.86). Our results highlight the importance of a "total diet" approach to improving survival among cancer patients.