The electrochemical copolymerization of 3,4-dihydroxybenzoic acid (3,4-DHBA) and aniline was carried out atmicrodisk gold electrodes by means of cyclic voltammetric sweep. The polymer obtained on the electrode shows goodelectrochemical activity and high stability even though in neutral and weakly basic media. It was found that theresponse current of ascorbic acid was greatly enhanced at this composite polymer electrode. Moreover, the anodicoverpotential was significantly reduced for about 200mV (vs. SCE) compared with that obtained at bare goldelectrodes. The electrode exhibits a rapid current response (less than 2 s) and a high sensitivity (0.21AM-1cm2).The dependence of response currents on the concentration of ascorbic acid was linear in the range of 1.0104-1.0102 M. In addition this composite polymer modified electrode exhibits a high electrode stability for along-term use.