The aim of this study was to evaluate a modified photo-Fenton procedure as a suitable advanced oxidative process to degrade antibiotics in aqueous solutions. The classical photo-Fenton procedure was modified using a photo-catalytic reactor with continuous recirculation, which was equipped with a high pressure cylindrically shaped mercury lamp centrally and coaxially positioned and surrounded by iron mesh. The oxidation of the organic substrate could occur simultaneously through homogeneous and heterogeneous photocatalytic mechanisms due to Fe2+ ions from the solution and Fe-0/Fe2+/3+ species formed on the surface of the iron mesh. The antibiotic degradation process was studied by monitoring the organic substrate concentration using chemical oxygen demand (COD), total organic carbon (TOC), high-performance liquid chromatography (HPLC) and Liquid chromatography coupled with mass spectrometry (LC-MS) analyses, in connection with monitoring the solution pH and the Fe2+/3+ concentration as function of the reaction time. During the oxidative process, the formation of iron oxy-hydroxyl species on the surface of the iron mesh and iron ionic species in the solution was observed. The efficiency of the antibiotics degradation, obtained using the modified photo-Fenton procedure is similar to that obtained through the classical photo-Fenton procedure. The advantage of this method is that it is a simple and inexpensive procedure. In addition, no additional materials with photo-catalytic activity are necessary for the procedure, and the initial pH of the solution no longer needs to be corrected. (c) 2013 Elsevier B.V. All rights reserved.