Technical Abstract: A brief review of trace and ultratrace elements from the nutritional point of view is presented. After defining the terms trace elements and ultratrace elements, and describing the basis for categorizing an element as essential, possibly essential, or having limited evidence for essentiality, the general importance of trace elements in the diet is discussed. Specific aspects of the nutritional and physiological importance of aluminum, arsenic, boron, bromine, cadmium, cobalt, fluorine, germanium, lead, lithium, manganese, molybdenum, nickel, rubidium, silicon, tin, and vanadium are presented. These aspects included reported deficiency signs in animals, other findings supporting essentiality including essential functions in lower forms of life, possible physiological and biochemical functions, and conditions that might enhance susceptibility to pathological consequences because of low dietary intake. The material presented indicates that all mineral elements essential for humans have not been identified and some trace and ultratrace elements may be of more importance in nutrition than currently acknowledged.