The arsenic, cadmium, mercury, and lead contents of 95 dietary supplement products were determined using microwave digestion and high-resolution inductively coupled plasma mass spectrometry. Precision and accuracy were demonstrated by element recovery from 17 dietary supplements and replicates of 8 reference materials. The concentration ranges were as follows: arsenic, <5-3770 microg/kg; cadmium, <10-368 microg/kg; mercury, <80-16800 microg/kg; and lead, <20-48600 microg/kg. An assessment of estimated exposures/intakes of the four elements is presented.