This European Standard specifies a method for the determination of decoquinate. This high-performance liquid chromatographic (HPLC) method with a fluorescence detection is applicable to the quantification of decoquinate content in complete and complementary compound feeds, medicated feeds, semi-liquid feeds, premixtures and feed additives. The method was fully validated from LOQ to 60 000 mg/kg on different matrices during an international collaborative study [11], especially on complete compound feeds for poultry, at trace contamination level of 3 mg/kg and at European authorized level of 20 mg/kg to 40 mg/kg [12]. The limit of detection is between 0,1 mg/kg and 0,3 mg/kg and the limit of quantification is around 0,5 mg/kg. These limits were validated during the collaborative study [11], from results on the blank feed. Lower limits of detection or quantification could be reached but a single laboratory validation is then requested.