In the past 20 years micronutrients have assumed great public health importance and a considerable amount of research has lead to increasing knowledge of their physiological role. Because it is a rapidly developing field, the WHO and FAO convened an Expert Consultation to evaluate the current state of knowledge. It had three main tasks: to review the full scope of vitamin and minerals requirements; to draft and adopt a report which would provide recommended nutrient intakes for vitamins A, C, D, E, and K; the B vitamins; calcium; iron; magnesium; zinc; selenium; and iodine; to identify key issues for future research and make preliminary recommendations for the handbook. This report contains the outcome of the Consultation, combined with up-to-date evidence that has since become available.