A visible-light driven photoelectrochemical degradation process has been applied to a solution polluted with the organophosphate insecticide chlorfenvinphos. Different WO3 nanosheets/nanorods have been used as photoanodes. These nanostructured electrodes have been fabricated by anodization of tungsten and, subsequently, they have been subjected to a thermal treatment (annealing). The combined influence of annealing temperature (400 degrees C and 600 degrees C) and operation pH (1 and 3) on the photoelectrocatalytic behavior of these nanorods has been examined through a statistical analysis. Morphological, structural and photoelectrochemical characterizations have also been carried out. The chlorfenvinphos degradation efficiency depended both on annealing temperature and, specially, operation pH. At pH 1 and using an annealing temperature of 600 degrees C, chlorfenvinphos has been effectively degraded following pseudo-first order kinetics with a coefficient of 7.8 x 10(-3) min(-1), and notably mineralized (more than 65% of Total Organic Carbon decrease).