Background and aims: It is still unclear whether a healthy diet can prevent heart failure (HF). Therefore, this study aimed to investigate the association between adherence to a Mediterranean-style diet, reflected by modified Mediterranean Diet Scores (mMDS), and the incidence of HF in men and women. Methods and results: This observational study comprised 9316 men and 27,645 women from the EPIC-NL cohort free from cardiovascular disease at baseline. Dietary intakes were assessed using a validated food frequency questionnaire. mMDS was calculated using a 9-point scale based on consumption of vegetables, legumes, fruit, nuts, seeds, grains, fish, fat ratio, dairy, meat and alcohol. HF events were ascertained by linkage to nationwide registries. Multivariable Hazard Ratios (HR) and 95% confidence intervals (CI) were estimated by Cox proportional hazards regression models. Over a median follow-up of 15 years (IQR 14e16), 633 HF events occurred: 144 in men (1.5%) and 489 in women (1.8%). The median mMDS was 4 (IQR 3e5). There was significant effect modification by sex (P-value for interaction <0.001), therefore results are stratified for men and women. For men, a higher mMDS associated with lower HF risk (HR: 0.88; 95% CI: 0.79, 0.98 per point increase in mMDS; HR upper category: 0.53; 95% CI: 0.33, 0.86), whereas no association was found in women (HR: 0.98; 95% CI: 0.93, 1.04 per point increase; HR upper category: 1.07; 95% CI: 0.83, 1.36). Conclusion: Adherence to a Mediterranean-style diet may reduce HF risk, particularly in men. The underlying reasons for the differences in findings between men and women need further study.