Copper electrodeposition on platinum electrodes from slightly acidic solutions of copper sulphate containing nicotinic acid (NA) is studied. The electrochemical results indicate that NA produces an inhibition of the copper deposition, probably related to the additive adsorption. Also, complex species formation between NA and cuprous ions occur at the interface. Nicotinic acid acts as a very effective brightener producing highly uniform and smooth surfaces of copper deposits. Surface morphology, brightness and adherence depend on the potential at which the deposition is performed.