Alpha-hexachlorocyclohexane (alpha-HCH) is dechlorinated by enzymes contained in rat liver cytosol and microsomes. An evidence was obtained that in the cytosol there are two alpha-HCH dechlorinating enzymes at least; one operates only in the presence of reduced glutathione (GSH) and catalyzes dechlorinations associated with the formation of another hydrophilic product. This product is probably a conjugate of the alpha-HCH-residue with GSH. The other cytoplasmic alpha-HCH-dechlorinase requires no additions. The microsomes, too, contain two alpha-HC dechlorinases at least: one is stimulated by GSH, the other by NADPH.