This chapter contains sections titled: Introduction Chemical Methods of Disinfection Chemical Nature and Occurrence of Disinfectant By-Products Associations of Human Disease with Drinking Water Disinfection General Toxicological Properties of Disinfectants General Toxicological Properties of Disinfectant By-Products Carcinogenic Properties of Disinfectants Carcinogenic By-Products of Disinfectants Effects of Disinfectants and Their By-Products on Reproduction Effects on Development By-Products of Potential Interest Summary and Conclusions Glossary References