Background: Previous studies show that oxidative stress is important in heart failure (HF) pathogenesis. The composite dietary antioxidant index (CDAI), which reflects the antioxidant profile of nutrient supplements, is associated with cardiovascular mortality risk. However, the association between CDAI and the risk of HF remains unknown. Hypothesis: In this study, we investigated the relationship between CDAI and HF risk using National Health and Nutritional Examination Survey (NHANES) data. Methods: The data of participants aged >40 years old from the NHNANES between 2001 and 2018 were obtained and used to assess the relationship between CDAI and the risk of HF. Logistic regression was used to calculate the odds ratio (OR) of CDAI for the risk of HF. Results: A total of 29 101 participants were divided into the HF (n = 1419; 4.88%) and non-HF groups (n = 27 682; 95.12%), HF group participants had lower CDAI than the non-HF group (-0.32 +/- 0.14 vs. 0.67 +/- 0.05, p <.0001). Compared with the lowest CDAI quartile (Q1), the OR for HF risk was 0.88 (0.68-1.13) for Q2 (p =.30), 0.77 (0.61-0.99) for Q3 (p =.04), and 0.68 (0.52-0.89) for Q4 (p = .01). Conclusions: CDAI was negatively associated with the risk of HF. Our findings show that the intake of an antioxidant-rich dietary is a potential method to reduce the risk of HF.