Zat warna direct red-23 merupakan pewarna sintetik dengan struktur senyawa organik yang bersifat non-biodegradable. Zat warna direct red-23 mengandung senyawa azo dan bersifat karsinogenik. Zat warna direct red-23 didegradasi secara fotolisis menggunakan sinar UV (ultraviolet), sinar matahari, tanpa dan dengan penambahan katalis C-N-codoped TiO2. Larutan zat warna direct red-23setelah dan sebelum didegradasi diukur dengan spektrofotometer UV-Vis pada panjang gelombang 400-800 nm. Penentuan berat optimum katalis C-N-codoped TiO2 dilakukan dengan metode fotolisis sinar UV dan didapatkan berat optimum 15 mg. Persen degradasi zat warna direct red-23 secara fotolisis sinar UV dan sinar matahari tanpa katalis C-N-codoped TiO2 27.47% dan 13.74%. Persen degradasi meningkat menjadi 68.68% dan 28.57% dengan penambahan 15 mg katalis C-N-codoped selama 120 menit fotolisis. Dari penelitian dapat disimpulkan metode fotolisis dengan sinar UV lebih efisien dibandingkan dengan sinar matahari. Direct red-23 dye is a synthetic dye that is widely used in textile industry. Wastes generated from textile industrial processes are generally non-biodegradable organic compounds containing azo compounds and carcinogenic. Direct red-23 dye was degraded by photolysis UV Light method,  solar irradiation, without and addition of C-N-codoped TiO2 catalyst. The results degradation of direct red-23 were measured with a UV-Vis spectrophotometer at wavelength of 400-800 nm. Determination of optimum weight of the C-N-codoped TiO2 catalyst was performedby photolysisUV Light methodand the optimum C-N-codoped TiO2catalyst is obtained 15 mg. Percent degradation of direct red-23 dye by photolysis of UV light and solar irradiation without C-N-codoped TiO2to 27.47% and 13.74%. Percent degradation increasedto 68.68% and 28.57% by addingC-N-codoped TiO2 catalyst was adding 120 menutes of photolysis.From the research it can be concluded by photolysis with UV Light methodis more efficient compared to solar radiation.