This International Standard specifies a gas chromatographic method for the determination of residues of organochlorine pesticides in animal feeding stuffs. The method is applicable to animal feeding stuffs containing residues of one or more of the following organochlorine pesticides and some of their isomers and degradation products: aldrin, op′-DDE, pp′-DDE, op′-DDT, pp′-DDT, dieldrin, endosulfan, endrin, HCB, α-HCH (α-BHC), β-HCH (β-BHC), γ-HCH (γ-BHC), δ-HCH (δ-BHC), heptachlor, heptachlor epoxide, op′-TDE (op′-DDD), pp′-TDE (pp′-DDD) and methoxychlor. The lower determination limit for these organochlorine pesticides is 0,005 mg/g. However, the lower determination limit is 0,01 mg/g for op′-DDT and pp′-DDT, and 0,05 mg/g for methoxychlor.