Natural organic matter (NOM) has been known to form undesirable disinfection byproducts (DBPs). Since EPA promulgated the Stage 1 disinfection byproducts rule (Stage 1 DBPR) in 1998, the removal of NOM, as a DBP precursor, has been regulated by enhanced coagulation. The MIEX(R) DOC resin target the removal of anionic constituents of NOM by exchanging the sites between anionic functional groups (e.g., carboxylic acids) and chloride ion (Cl-). This research focused on characterization of MIEX adsorption of NOM isolates and bulk NOM from natural waters. An enhanced coagulation matrix (source waters with varying TOC and alkalinity) was used as a framework for identifying and selecting natural waters from around the U.S. In all cases, based on XAD 8/4 resin fractionation of raw and MIEX treated waters, effective removals of hydrophobic, transphilic, and hydrophilic NOM acids were observed. The removals of transphilic and hydrophilic (low molecular weight) acids are noteworthy, given the ineffectiveness of coagulation in removing these polar NOM fractions. Includes 4 references, tables, figures.