A new x-ray fluorescence method for the ultratrace analysis of metals has been developed. The metal to be determined is first isolated by conventional chemical methods. It is then taken up from water or dilute acid solution by a tiny disk of a strong-acid type cation exchange resin or a strong-base type anion exchange resin and determined by x-ray analysis using a fully-focused curved-crystal x-ray milliprobe. The method can be used for the trace analysis of 28 or more cationic metals or 15 or more anionic metals. As little as 0.01 micron grams of the more sensitive metals can be determined.