Little information is available on absorption and metabolism of minerals and trace elements during infancy. The lack of data is related to the methodological problems involved in these studies. By using stable isotopes as labels, studies can be conducted in infants without introducing exposure to radiation, or any other risk, and studies on bioavailability of minerals and trace elements during early life can therefore be performed. This paper discusses results from studies of trace element/mineral absorption and metabolism in infants, based on stable isotope techniques.