Atrazine is a persistent herbicide and several studies have detected their presence in drinking water sources. In this work the atrazine photocatalytic degradation was investigated in aqueous solution using TiO2, ZnO and TiO2/ZnO catalysts. The catalysts were synthesized by Pechini's method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The process was monitored using absorption spectroscopy in ultraviolet and visible (UV-vis) region and high performance liquid chromatography (HPLC). The prepared catalysts were used in ultrafine powder form and its characterization showed nanometer order particle sizes. The atrazine absorbance decrease was observed after samples irradiation in catalysts presence and HPLC analysis showed a significant herbicide reduction and other compounds formation as degradation products. The ZnO catalyst use was more effective in atrazine molecule degradation compared to the other nanoparticles.