Catechol can be oxidized electrochemically to its corresponding o-benzoquinone. The electrogenerated quinone can be deposited by cycling the potential at the surface of glassy carbon electrodes. We have studied the electrochemical features of films derived from catechol by cyclic voltammetry. The electrodeposited film shows stable reversible redox response, dependent on pH as anticipated for quinone/catechol functionalities. Glassy carbon electrodes covered with a film derived from catechol exhibit catalytic activity in the electrooxidation of NADH at a low potential. The catalytic current is proportional to the concentration of NADH over the range 0.02–0.34 mM.