This document specifies a high-performance liquid chromatographic (HPLC) mass spectrometric (MS) method for screening and quantification of melamine and cyanuric acid in the concentration range between 1 mg/kg and 100 mg/kg feed.The method is validated in an international collaborative trial for melamine in complete feed, complementary feed, feed material, milk replacer and pet food including canned pet food in the range between 1 mg/kg and 80 mg/kg with particular regard to the maximum level of 2,5 mg/kg as established by the European Commission.Laboratory experiences have shown that the method is also applicable for cyanuric acid in the same concentration range in complete feed (n = 7), complementary feed (n = 6), feed material (n = 7, resp. 9), milk replacer (n = 7) and pet food (n = 7) including canned pet food.Since the LC-MS/MS sensitivity for cyanuric acid is lower than for melamine, it has to be ensured that the LC-MS/MS system is in excellent working order. The method is applicable to feeding stuffs but not tested for pre-mixtures and feed additives.Quantification of concentrations above 100 mg/kg is possible, but the method has to be validated by the operator.