Photocatalyzed degradation of uracil (1) and 5-bromouracil (2) has been investigated in aqueous suspensions of titanium dioxide under a variety of conditions. The degradation was studied by monitoring the change in substrate concentration employing UV spectroscopic analysis technique and depletion in total organic carbon (TOC) content as a function of irradiation time. The degradation of the compounds under investigation was studied using various parameters such as, different types of TiO2 powders, pH, catalyst concentration, substrate concentrations, and in the presence of electron acceptors like hydrogen peroxide (H2O2) and potassium bromate (KBrO3) besides molecular oxygen. Photocatalyst Degussa P25 was found to be more efficient for the degradation of both compounds as compared with other TiO, powders such as UV100, PC500 and TTR (c) 2006 Elsevier B.V. All rights reserved.