To ensure a sustainable development, it is essential to better characterize the relationships between diet sustainability and health. We investigated the associations between sustainable dietary patterns, assessed using the Sustainable Diet Index (SDI) and the risk of cancer and cardiovascular diseases in a large prospective cohort of French volunteers. We computed the SDI among 25,592 participants of the NutriNet-Santé cohort using a database developed within the BioNutriNet project comprising nutritional, behavioral, environmental and economic data. Health status of each participant was collected from 2014 to 2018 and validated by physicians. Associations between the SDI and risk of chronic diseases (cancer and cardiovas-cular diseases) were assessed using multivariable Cox models. 640 incident chronic diseases occurred during the 3.8-year follow-up (483 cancer cases and 158 cardiovascular disease cases). A higher SDI was associated with a lower risk of overall chronic diseases after adjustment for potential confounding factors. Participants in the fourth quartile, reflecting the highest sustainable dietary patterns, exhibited a significant decrease in risk of cancers or cardiovascular diseases (HR Q4 vs. Q1 = 0.61 (95% CI 0.47-0.80), P-trend = 0.0002). More specifically, this association was observed for cancers in the fully adjusted model but was not statistically significant for cardiovascular diseases. Although these results need to be confirmed by other observational studies, they support the fact that a wide adoption of sustainable dietary patterns may contribute to improving global health in France and argue for existing dietary patterns exhibiting cobenefits for human health and the environment.