Introduction. Prevention and control of environmental pollution is one of the main responsibilities and preoccupations of modern men. In recent years, a significant number of research works have been being done in order to prevent and control of such pollution. Among these, photodegradation of pollutants is a part of the advanced oxidation technologies, which aims to reduct and/or elliminate toxic and persistent compounds such as pesticides, which are now part of the environment. Objective. To evaluate the photo degradation of the Mertect pesticide, by the use of photofenton with an ultra violet light lamp. Materials and methods. An experimental factorial 2x3 design was used, and an ultra violet light lamp was used for it. Also, a glass vat was used to keep the pesticide solution to be