Experimental investigations have been performed, using cyclic and linear sweep Voltammetry, to determine the effects of Nigella sativa essential oil additive (NS) on the electrodeposition of tin on mild steel in acid sulfuric solution. The experiments were performed under different plating time, different current densities, pH and temperature conditions. Tin electrodeposition on mild steel was performed using a DC -supply at denoted operating parameters. The presence of the NS additive caused an increase of the activation energy and of the overvoltage of the reduction of hydrogen and stannous ions. The surface of the plated steel was examined using Scanning electron microscope. Different surface characteristics were obtained depending upon the presence or free-additive. The electrodeposition rate of the plated surface was also determined by a gravimetric technique. The quality of the electro-deposition of tin, in the presence of Nigella sativa, was good as indicated by the microstructural morphology of the plated surface except for the few porosities demonstrated.