The elimination of contaminants of emerging concern (CECs) during conventional wastewater treatment is not complete, and therefore, different amounts of these compounds are continuously released via wastewater effluents into the aquatic environment. This constitutes a major issue for water reuse, because these compounds can undergo transformation in the environment or during disinfection if reclaimed water is used for drinking water production. Different emerging contaminants, e.g., perfluorinated compounds, pharmaceuticals, antibacterials, plasticizers, and preservatives, and transformation products, which are in some cases more toxic than original compounds, have been occasionally found in finished drinking waters. The present chapter reviews the CECs detected in drinking water and the disinfection by-products generated by different CECs present in the aquatic environment. Moreover, the potential toxicologic effects that these pollutants and their transformation products pose for human health are also reviewed. Levels of these compounds in treated waters, and therefore exposure, could be reduced by the use of advanced removal technologies.