This method is for determining platinum, rhodium and rhenium, in fresh and regenerated catalysts composed of alumina or silica/alumina by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). Additionally, modifiers such as tin, indium, lithium, potassium, cerium and lanthanum can also be determined. Platinum and rhenium can be determined within the concentration range of 0.1 to 1.0 mass-% when a 1-g sample of catalyst is used for the analysis, while rhodium can be determined down to 0.01 mass-%. The tin, indium and lithium concentration range is generally 0.1 to 0.7 mass-%. Potassium, cerium and lanthanum can be determined from 0.5 to several mass-%. The method is sufficiently flexible to add more elemental analyses if needed.