This document specifies a liquid chromatographic method with triple-quadrupole mass spectrometry (MS/MS) detection for the determination of pentachlorophenol (PCP) in feed materials and animal feed. The limit of quantitation (LOQ) for the PCP determination in guar gum@ fatty acid distillates (FAD) and animal feed is 10 ??/kg. Individual laboratories are responsible for ensuring that the equipment that they use will achieve this limit of quantification. The method is validated in an international collaborative trial for pentachlorophenol in compound feed@ guar gum and fatty acid distillate in the range between 9 ??/kg and 22 ??/kg. The results of the collaborative trial@ in which 16 laboratories participated@ have shown that the method is applicable for the determination of PCP in compound feed@ guar gum and FAD at the desired limit of 10 ??/kg. Satisfactory results were obtained for one compound feed sample@ guar gum and the two FAD samples (HorRat <2)@ while for the second compound feed sample a HorRat value of 2@2 was obtained.