ABSTRACT Potentiodynamically fabricated poly(alizarin red s) modified glassy carbon electrode was characterized using cyclic voltammetry and electrochemical impedance spectroscopy. Cyclic voltammetric response of the polymer modified electrode towards [Fe(CN)6]3-/4- probe and the calculated charge transfer resistance and double layer capacitance value from electrochemical impedance data confirmed surface modification of the glassy carbon electrode. Cyclic voltammetric investigation of metronidazole at poly(alizarin red s) modified glassy carbon electrode revealed an irreversible reduction peak centered at about -0.68 V. The observed peak potential shift with increasing pH in the range 4.0-10.0 indicated the involvement of protons during the reduction of metronidazole, the peak potential shift observed with scan rate in the range 20–300 mV/s confirmed the irreversibility of the reduction reaction of metronidazole at the poly(alizarin red s)modified glassy carbon electrode. A better determination coefficient (R2) for the dependence of peak current on the scan rate than on the square root of scan rate indicated that the reduction reaction was predominantly charge transfer controlled kinetics. Under the optimized square wave adsorptive stripping voltammetric method and solution parameters, an excellent determination coefficient (R2) of 0.9991 for linear dependence of reduction peak current on concentration in the range 25 -125 µM, method detection limit of 3.75× 10-7M, method quantification limit of 1.25×10-6 M, recovery result of 98% for spiked standard metronidazole in tablet sample and 90.0-100% recovery of metronidazole in tablet sample in the presence of 100 and 150% of uric acid and ascorbic acid , validated the applicability of the present method for determination of metronidazole in real samples including tablet formulation. The metronidazole content of the tested tablet formulation was found to be 97.6% of what is claimed by the tablet manufacturer making the developed method an excellent potential candidate for its applicability for metronidazole determination in any real sample. Keywords: Alizarin red s; Electrochemical; Metronidazole; Modified electrode; Pharmaceutical tablet formulation