A new electrochemical sensor based on gold nanoparticles mesoporous silica modified carbon paste electrode (AuNPs-MPS) was developed for simultaneous determination of hydroquinone and catechol. Morphology and structure of the AuNPs-MPS were characterized by transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The electrochemical behavior of hydroquinone and catechol were investigated using square wave voltammetry and the results indicate that the electrochemical responses are improved significantly at the modified electrode. The observed oxidative peaks separation of about 120 mV made possible the simultaneous determination of hydroquinone and catechol in their binary-mixture. Under the optimized condition, a linear dynamic range of 10.0 mu M-1.0 mM range for hydroquinone with the detection limit of 1.2 mu M and from 30.0 mu M-1.0 mM for catechol with the detection limit of 1.1 mu M were obtained. The applicability of the method was demonstrated by the recovery studies of hydroquinone and catechol in spiked tap water samples. (C) 2016 Elsevier B.V. All rights reserved.