Abstract. Cassava (Manihot utilissima) is the main raw material of tapioca flour industry. The tapioca industry waste water still contains high enough BOD, COD, and cyanide, above the quality standard of industrial waste water. Photo-Fenton is one of the most effective alternative methods of degrading organic pollutants. This study aims to determine the effect of Photo-Fenton method on the degradation of organic pollutants such as COD and cyanide. For operating conditions of this study use the addition of concentrations of H 2 O 2 and FeSO 4 .7H 2 O and different UV light intensity. The analysis of COD concentration using SNI method is spectrophotometric. From the research result, it is found that the concentration of COD and cyanide in tapioca waste can be reduced by using Photo-Fenton method. With initial COD content of 6000 mg/L and cyanide level of 0.67 mg/L. And in the operating conditions of the addition of 5 ml/l of H 2 O 2 , Fe 2+ 1.25 mg/l, and light intensity of 200 lm, the highest COD and cyanide levels were found to be 900 mg/l for COD and 0.08 mg/l for cyanide. Final levels of COD up to 900 mg/l and cyanide concentrations up to 0.08 mg/l.