Background: Vitamin D intake may play a key role in the prevention of cardiovascular disease. Objective: We evaluated associations of dietary and supplemental vitamin D intake with the 20-y incidence of metabolic syndrome. Design: Data from 4727 black and white young men and women from the Coronary Artery Risk Development in Young Adults study were used to examine relations of dietary plus supplemental vitamin D intake with the incidence of metabolic syndrome (as defined by Adult Treatment Panel, third report, guidelines) and the prevalence of its components, including abdominal obesity, elevated blood pressure, and high glucose, low HDL, and high triglyceride concentrations. Results: The intake of vitamin D from dietary and supplemental sources was inversely related to the 20-y cumulative prevalence of abdominal obesity (P = 0.05) and high glucose (P = 0.02) and low HDL (P = 0.004) concentrations after adjustment for age, sex, race, education, center, and energy intake. In comparison with the lowest intake quintile (quintile 1), HRs (95% CIs) of developing incident metabolic syndrome for quintiles 2-5 of vitamin D intake were 0.82 (0.67, 1.00), 0.84 (0.68, 1.03), 0.70 (0.56, 0.88), and 0.82 (95% CI: 0.65, 1.02), respectively (P-trend = 0.03) after adjustment for demographic and lifestyle factors. Conclusions: In young adults, the dietary plus supplemental vitamin D intake was inversely related to the development of incident metabolic syndrome over 20 y of follow-up. These findings support the recommendations of the Dietary Guidelines for Americans to increase intakes of vitamin D-rich foods, such as milk and fish.