Since the discovery of disinfection by-products (DBPs) in drinking water in the 1970s and with increasing understanding about their occurrence and health effects, the control of DBP formation has become one of the major issues for the drinking water industry. A significant amount of research has been conducted on trihalomethanes (THMs) and haloacetic acids (HAAs), the two regulated (in the United States [U.S.]) and largest classes of DBPs (on a weight basis). In addition to other measured DBPs, the sum of known DBPs has accounted for 30 to 60% of the total organic halogen (TOX) detected during chlorination, which is the oldest and the most commonly used disinfection technique in water treatment around the world. As a result, the formation and control of THMs and HAAs and other DBPs have been widely researched and discussed in the literature (1-4). However, recent research has shown that there are many emerging DBPs of health concern in drinking waters. The objective of this chapter is to summarize the recent advances in understanding DBP formation, occurrence, control, health effects, and regulations that have occurred mainly within the past five years. It was noteworthy that inorganic DBPs (e.g., bromate, chlorate, chlorite) have received less attention over the past few years as compared to emerging organic DBPs that exhibit high geno- And cytotoxicity.