Phenazopyridine hydrochloride is an antiviral effective drug active compound. A glassy carbon electrode (GCE) was modified with an electropolymerized film of p-aminobenzene sulfonic acid (p-ABSA) in phosphate buffer solution (PBS). The electrochemical properties of the polymer film were studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The polymer film-modified electrode was used to electrochemically detect phenazopyridine hydrochloride. Polymer film showed excellent electrocatalytic activity for the reduction of phenazopyridine hydrochloride. The catodic peak potential value of the phenazopyridine hydrochloride at the poly(p-ABSA) modified glassy carbon electrode was -334 mV obtained by DPV. A linear calibration curve for DPV analysis was constructed in the phenazopyridine hydrochloride concentration range 6x10(-6)-1x10(-5) mol L-1. Limit of detection (LOD) and limit of quantification (LOQ) were obtained as 2.1x10(-7) and 7x10(-7) mol L-1 respectively. The proposed method exhibits good recovery and reproducibility. The mechanisms of electropolymerization of p-ABSA are also suggested.