Technical Abstract: This article provides an overview of the most current research on flavonoids, which was presented during a workshop entitled, “Flavonoids and Heart Health,” held by the ILSI North America Project Committee on Flavonoids in Washington, DC, May 31 and June 1, 2005. Because a thorough knowledge and understanding about the science of flavonoids and their effect on health will aid in establishing dietary recommendations for bioactive components such as flavonoids, a systematic review of the science of select flavonoid classes (i.e., flavonols, flavones, flavanones, isoflavones, flavan-3-ols, anthocyanins, and proanthocyanidins) was presented. The objectives of the workshop were to: (1) present and discuss the most current research on flavonoid intake and the relation between flavonoids and heart health; (2) develop information that could lead to expert consensus on the state-of-the-science on dietary intake of flavonoids on heart health; and (3) summarize and prioritize the research needed to establish the relationships between specific flavonoids and heart health. Presentations included the basics of the biology of flavonoids, including the types and distribution in foods, analytical methodologies used to determine the amounts in foods, the bioavailability, the consumption patterns and potential biomarkers of intake, risk assessment and safety evaluation, structure/function claims, and the proposed mechanism(s) of the relationship between certain flavonoids and heart health endpoints. Data presented support the concept that certain flavonoids in the diet may be associated with significant health benefits, including heart health. Research gaps were identified to help move the science forward.