Background: Diet diversity and quality are each recommended to promote a healthy diet and prevent chronic disease. Yet, little is known on how diet diversity relates to diet quality or cardiometabolic health, particularly in underrepresented subgroups disproportionally affected by poor nutrition and CVD. Aims: To determine relationships of 1) dietary diversity with diet quality, and 2) diet diversity and quality with CVD risk factors (blood pressure, plasma LDL-C, HDL-C, triglycerides, total:HDL ratio, CRP, glucose) in a diverse population of U.S. adults. Methods: We evaluated 21,350 Black and White adults aged ≥45 years in REGARDS. A validated dietary questionnaire at baseline was used to estimate two distinct aspects of diet diversity: food count (no. of food items eaten at least once a week) and dissimilarity (Jaccard distance, capturing diversity of attributes of foods eaten). Diet quality was estimated using the AHA-2020 and AHEI-2010 scores. Cross-sectional associations with CVD risk factors were examined using multivariable linear regression. Results: Food count and dissimilarity each inversely correlated with diet quality scores (r ranging from -0.04 to -0.11). In multivariable models, diet diversity had mixed or mostly null associations with CVD risk factors (See Table). For instance, food count inversely associated with HDL-C and LDL-C; while dissimilarity inversely associated with plasma glucose but positively with triglycerides. In contrast, AHA-2020 and AHEI-2010 were consistently favorably associated with nearly all CVD risk factors. Associations of diet diversity were similar in Blacks and Whites, while most associations of diet quality were stronger among Whites ( P -interaction < 0.0015). Conclusion: Diet diversity metrics were not associated with diet healthfulness or most CVD risk factors among U.S. adults. Our findings support a focus on diet quality, with adequate intake of healthful food groups, rather than diversity, to promote cardiometabolic health.