Objectives: The aim of this study was to investigate the relationship between malnutrition and long-term survival in patients who underwent cardiopulmonary bypass (CPB). Methods: This study analyzed the long-term survival data of a mixed cohort of 1187 cardiac patients previously enrolled in a prospective observational study of nutritional screening in cardiac surgery. Nutritional status was assessed using the Malnutrition Universal Screening Tool (MUST). The mean age of patients was 58.86 ± 10.07 y (95% confidence interval [CI], 58.2–59.4). The median time of follow-up was 73.4 mo (25th–75th percentiles, 18.3–101.3). Results: In all, 449 patients (37.8%) were lost to follow-up after hospitalization. For the remaining participants, the overall 8-y survival was 68% (95% CI, 59–76) and 77% (95% CI, 73–80; log-rank, P = 0.12) in patients with and without malnutrition risk, respectively. Statistically significant differences in survival were found during the 3-y follow-up of patients with heart valve disease: 83% (95% CI, 74–92) with malnutrition versus 93% (95% CI, 90–96) without malnutrition (log-rank, P = 0.03). The final multivariate Cox regression model revealed logistic EuroSCORE (hazard ratio (HR), 1.337; 95% CI, 1.110–1.612), cardiopulmonary bypass time <110.5 min (HR 0.463, 95% CI 0.255–0.842), preoperative albumin (HR 0.799, 95% CI 0.691–0.924), and C-reactive protein (HR, 1.106; 95% CI, 1.018–1.202) as independent predictors of 3-y survival. Conclusion: Preoperative malnutrition is not associated with 8-y mortality in a mixed cardiac surgery cohort. However, it may be associated with worse 3-y outcomes in patients with heart valve disease.