Natural organic matter (NOM) removal is an important issue in drinking water treatment processes. This study investigated NOM removal in lake water using a combined photocatalysis/microfiltration (MF) system. The system performances for treatment of natural water were evaluated in terms of dissolved organic carbon (DOC), UV₂₅₄ absorbance removal efficiency, and transmembrane pressure. The addition of iron oxide particles (IOP) into feedwater, coating of membranes with IOP, and TiO₂ surface modification were carried out to examine their effects on NOM removal efficiency. The change of transmembrane pressure was monitored during continuous MF operation to establish the correlation between NOM removal efficiency and membrane permeability.