Use of hollow fiber microfiltration membranes (HFMF) for the separation of photocatalysts was investigated during batch and continuous operations for treatment of synthetic feed water containing humic acids and background species. Treatment efficiencies for natural organic matter were evaluated in terms of TOC and UV254 absorbance removal, while the degree of membrane fouling was assessed based on pressure buildup and relative permeability ratio. Nearly complete UV removal was achieved for the 270-min photocatalytic reaction period, although TOC itself was found partially mineralized. Aggregation of TiO2 and humic acids caused a substantial increase in transmembrane pressure at the early stage of operation, but photocatalytic degradation helped reduce the pressure.