Brominated flame retardants have been widely used in industry. There is a rapid growing public concern for their availabilities in the environment. Advanced oxidation process (AOP) is a promising and efficient technology which may be used to remove emerging chemicals such as brominated flame retardants. This study aims at investigating optimal operational conditions for the removal of BDE-209 using nano-scaled titanium(IV) oxide. The residual PBDE congeners after photocatalytical degradation of BDE-209 by TiO2 were analysed by gas chromatography-mass spectrometry (GC-MS). It was found that the degradability of BDE-209 by TiO2 was attributed to its photocatalytic activity but not the small size of the particles. The half-life of removing BDE-209 by TiO2 was 3.05 days under visible light. Tetra- and penta-BDEs were the major degraded products of BDE-209. Optimum conditions for photocatalytical degradation of BDE-209 was found to be at pH 12 (93% +/- 1%), 5, 10, 20 mg/L (93.0% +/- 1.70%, 91.6% +/- 3.21%, 91.9% +/- 0.952%, respectively), respectively of humic acid and in the form of anatase/rutile TiO2 (82% +/- 3%). Hence, the efficiency of removing BDE-209 can be maximized while being cost effective at the said operating conditions.