The photocatalytic degradation of cefixime was studied using NiO/nano-clinoptilolite (NiO/NCP) as a heterogeneous photocatalyst under Hg-lamp irradiation. For this goal, nano-particles of clinoptilolite (NCP) prepared via mechanical ball-mill method were ion exchanged, calcined and characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), transmission electron microscope (TEM) and Fourier transformation infra red (FT-IR) techniques. The degradation process was monitored during the experimental runs by UV-vis absorption spectroscopy as well as COD and HPLC methods. The best degradation results were obtained at the following optimal conditions: 0.25 g L-1 of the photocatalyst containing 13.3% NiO, 50 times diluted cefixime solution at pH 5. The kinetics of the process was well modeled by the first order (Langmuir-Hinshelwood) model. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.