Titanium dioxide (TiO 2 ) was used as a photocatalyst for the detoxification of water containing methyl orange (MO), which was used as a model compound. Solar radiation was used as an irradiation source. It was found that there was no degradation for the MO in the dark and in the presence of TiO 2 . Also no degradation was observed for MO when the solution placed under solar radiation but without TiO 2 . Several experiments were used to optimize the experimental parameters. In the first set of experiments variable amounts of TiO 2 were used with a fixed concentration of MO. It was found that 0.4% of TiO 2 gave the highest degradation rate constant, 0.619h - 1 . In the second set of experiments TiO 2 concentration was fixed at 0.4% and the MO concentration was varied, the highest rate constants was obtained when the concentration of MO was 4x10 - 5 M and it was found to be 0.639h - 1 . The degradation became negligible in the presence of high concentrations of MO. The highest degradation rate was obtained at pH=3 with a rate constant κ=2.6683h - 1 , followed by that at pH=9 where the calculated κ=0.7585h - 1 .