SummaryDiet samples were collected by a duplicated portion study for an adult male in both Mito, Japan and Los Alamos, U. S. A. The ashed samples were analyzed with inductively coupled plasma mass spectro metry (ICP-MS) and inductively coupled atomic emission spectrometry (ICP-AES) for 22 elements. The trace and ultratrace elements, Ba, Mo, Ni, Co, Cd, Cs, Tl, Pb, Bi, Th, and U were determined by ICP-MS. The major and minor elements, Na, K, P, Ca, Mg, Fe, Zn, Mn, Al, Sr, and Cu were determined by ICP-AES. Accuracy and precision for some elements were examined by analyzing National Institute of Standards and Technology (formerly National Bureau of Standards) Standard Reference Materials, 1577b Bovine Liver, and 1573 Tomato Leaves. Simultaneous multielement analyses of diet samples by using the two methods were found to be very useful.