The Chemical Substances Control Law (CSCL) in Japan was enacted in 1973 to prevent environmental pollution by chemical substances. Since then, the CSCL has played an important role in managing many chemical substances developed and used in Japan. The CSCL requires various hazard information of new chemical substances (in other words, results of safety tests) before manufacturing or importing them. This review article describes the purpose, background and system of the CSCL, and the safety test methods to apply for new chemical substances.