Abstract: Carbon nanotubes modified with silver (Ag-CNTs) were used for the fabrication of Ag-CNT/TiO₂ composite electrodes. The electrodes were characterized by X-ray diffraction, transmission and scanning electron microscopy, and energy dispersive Xray analysis. It was found that TiO2 particles were distributed uniformly in the CNT networks, and silver particles were fixed on the surface of the CNTs. . The composite electrodes exhibited a high photoelectrocatalytic (PEC) activity. The PEC degradation efficiency for methylene blue (MB) was a synergistic effect of photodegradation of TiO₂, increased electrical conductivity by the CNT networks, an effect of the silver and a function of the applied potential. Especially, the composites treated with silver revealed an enhanced photo-degradation ability for MB and the PEC activity increased with increasing silver content.