The photocatalytic degradation of an azo dye derivative, chrysoidine Y (1), was investigated in aqueous suspensions of titanium dioxide and zinc oxide by monitoring the change in substrate concentration employing UV spectroscopic analysis and decrease in total organic carbon content as a function of irradiation time under a variety of conditions. The degradation of the dye was studied under different conditions such as pH, catalyst concentration, substrate concentration and in the presence of electron acceptors such as hydrogen peroxide (H2O2) and potassium bromate (KBrO3) besides molecular oxygen. The degradation rates were found to be strongly influenced by all the above parameters. The photocatalyst Degussa P25 was found to be more efficient as compared with zinc oxide.