Decolorization of Reactive Red 141 by an organoclay was investigated. The organoclay was synthesized in laboratory conditions by using a cationic surfactant (hexadecyltrimethylammoniumbromide) in an amount equivalent to 100% of the cation exchange capacity of bentonite. The surface modification of bentonite with the surfactant was examined using X-ray diffraction and the Fourier transform infrared spectroscopic technique. Adsorption isotherms and equilibrium adsorption capacities were determined by the fitting of the experimental data to three well-known isotherm models: Langmuir, Freundlich and Sips (Langmuir-Freundlich). Results indicated that the decolorization was dependent on contact time, initial dye concentration, adsorbent dosage and temperature. An artificial neural network model was developed to predict the decolorization of the Reactive Red 141 solution. It was concluded that artificial neural network provided reasonable predictive performance. Simulations based on the developed artificial neural network model can estimate the behavior of the decolorization process under different conditions. (C) 2012 Elsevier Ltd. All rights reserved.