A paper‐chromatographic method has been developed for the separation and detection of the constituents of BHC (benzene hexachloride) and chlordane, and the behaviour of Toxaphene and DDT on paper was also observed. Acetic anhydride was used as the fixed phase with n‐hexane or light‐petroleum fractions as the moving solvent. The method should be of value in the separation and identification of traces of materials present as contaminations after the use of dusts and sprays on crops. The method has been applied to the quantitative estimation of y‐hexachlorocyclohexane in insecticidal preparations, on a micro‐scale using sheets of filter paper, and on a larger scale using columns of hydrocellulose.