The objective of this research is to examine the interaction of select heavy metals and natural organic matter (NOM) during coagulation and the metal preoxidation process before coagulation/adsorption for drinking water treatment. The metals used in this study include copper and arsenic, which are commonly found in source drinking water and represent metal cations and metal anions respectively. This research focuses on the investigation of copper-NOM (i.e., Cu(II)-NOM) interaction during coagulation/co-precipitation with aluminum based coagulants (Chapter 3), the arsenic redox speciation distribution in synthetic raw waters with the presence of NOM (Chapter 4), and the effect of NOM on arsenite (As(III)) and arsenate (As(V)) adsorption onto TiO2 surface (Chapter 5 and Chapter 6). The results suggest that the presence of Cu(II) in raw waters can facilitate NOM removal by coagulation. The effect of NOM on Cu(II) co-precipitation with alum is dependent on water pH. When pH is relatively low and no Cu(OH)2(s) or CuCO3(s) precipitates out, NOM can increase Cu(II) removal, whereas when pH is high and Cu(OH)2(s) or CuCO3(s) precipitates exist, NOM can inhibit Cu(II) removal through the coagulation (co-precipitation) with alum. The presence of NOM can mediate arsenic redox speciation distribution in a synthetic raw water. NOM can also facilitate As(III) oxidation by TiO2 in the absence of light and oxygen. Both As(III) and As(V) adsorption onto TiO2 surface can be decreased by the presence of NOM in raw water. This research addresses the important issue of how interactions between select heavy metals and NOM affects their ultimate fate during drinking water treatment processes. The experimental results provide insightful information for drinking water treatment plants to optimize operational conditions in order to remove select heavy metals and NOM from water.