Background <p>The dietary index of gut microbiota (DI-GM) is a newly proposed index for assessing dietary quality, and studies on its association with cardiovascular disease (CVD) are limited. This study aimed to investigate the association between DI-GM and the prevalence of CVD.</p> Methods <p>We utilized data from the National Health and Nutrition Examination Survey (NHANES). Logistic regression analyses were performed to examine the association between DI-GM and CVD. Smoothed curve fitting was employed to explore potential nonlinear relationships. Additionally, subgroup analyses were conducted to assess the stability of the results.</p> Results <p>The study included 22,590 participants, of whom 20,216 had no CVD and 2,374 had CVD. After adjusting for all covariates, the DI-GM score was significantly negatively associated with CVD risk, with a 4% reduction in CVD risk for each unit increase in DI-GM score (OR = 0.96, 95% CI: 0.94–0.99, <i>P</i> = 0.015). Notably, the highest DI-GM score group (6–12) had a 13% lower risk of CVD compared to the lowest DI-GM score group (0–3) (OR = 0.87, 95% CI: 0.76-1.00, <i>P</i> = 0.048). </p> Conclusion <p>The research results indicate that a higher DI-GM score protects against CVD, providing crucial empirical support for dietary intervention strategies based on gut microbiota modulation.</p> Clinical trial number <p>Not applicable.</p>