The role of vitamin D in regulation of calcium and phosphate metabolism has widely been recognized for many years. More recent research has focused on the role of vitamin D in gene expression for proteins that may limit cancer growth and have other health implications. The symposium speakers will review the latest research on the biology of and requirements for vitamin D. The use of existing and new chemical forms and complexes with vitamin D will be presented, along with a supplier’s perspective on vitamin D fortification of dairy and other foods. Presentations and discussion will address potential and rationale for additional food fortification with vitamin D. Speakers will be asked to address some or all of the following questions: (1) How convincing is the evidence that more dietary vitamin D is needed? (2) What is the likelihood the adequate intake (AI) and the recommended dietary allowance (RDA) can be increased? (3) How would a change in the recommendation impact consumer intakes? (4) How should the food industry respond to a change in recommended intake? (5) Should fortification be adjusted for bioavailability?