A selective and sensitive electrochemical sensor based on glassy carbon electrode modified with poly (malachite green) was developed for determination of tetracycline in pharmaceutical tablet formulation. Potentiodaynamically deposited poly(malachite green) on the surface of glassy carbon electrode from aqueous malachite green solution was characterized using cyclic voltammetry and electrochemical impedance spectroscopy using [Fe(CN) ix 6 ] 3-/4- as a probe. In contrast to the unmodified glassy carbon electrode, the fabricated poly(malachite green) modified glassy carbon electrode showed catalytic property towards two steps irreversible oxidation of tetracycline which might be attributed to the increased surface area. Better correlation of the oxidative peak current with the scan rate than with the square root of scan rate indicated that the oxidation reaction of tetracycline at the polymer modified electrode is predominantly controlled by electron exchange step at the solution polymer interface. Under optimized solution pH, accumulation potential and accumulation time, the square wave adsorptive anodic stripping peak current response of the polymer modified electrode showed linear dependence on concentration of tetracycline in the range of 5-100 µM with determination coefficient (R 2 ), method detection limit, and quantification limit of 0.995, 1.6 µM and 5.3 µM, respectively. The tetracycline content of a tablet sample claimed 250 mg/tablet was found to be 262.5 mg/tablet with a 5% deviation. The applicability of the present method using poly (malachite green) modified glassy carbon electrode for determination of tetracycline was validated using spike recovery and interference study. Excellent recovery result of 101.75% for spiked standard tetracycline, and percent errors in the range of 0.0-5.3, 0.9-4.0, and 1.8-8.0% for 50-200% of uric acid, ascorbic acid, and ampicillin, respectively confirmed that the method can be applied for determination of tetracycline in tablet formulation