Abstract:Hexachlorocyclohexane (HCH) is a halogenated organic insecticide, which was once extensively used all over the world for agricultural and public health purposes. Its use has been restricted or banned in the developed countries due to its high toxicity and long persistence. However, HCH is still used in some developing countries. Even in those countries, where the use of HCH has been stopped for many years, the problem of residues still existed. In this article, we summarized the latest progress in the research of the diversity of HCH-degrading microorganisms and the degradation pathway on the four main HCH-isomers (α-, β-, γ- and δ-HCH), which will provide the reference for the economical and feasible bioremediation strategy on the HCH polluted environment.