Disinfection is practiced to minimize the occurrence and growth of microbial pathogens and thus ensure the hygienic safety of swimming pool water. However, potentially hazardous disinfection by-products (DBPs) are formed from the reaction between disinfectants and DBP precursors. This chapter discusses the formation of these DBPs in swimming pool water and modeling approaches for quantification of their levels given estimates of anthropogenic contaminant input in swimming pools. Promising DBP control technologies are also discussed. Overview of the three key aspects related to swimming pool water help readers to better understand the profile of DBPs and their control in swimming pool water.