Glassy carbon electrodes were modified with thin films of unsubstituted cobalt phthalocyanine (CoPc), prepared at the surface of an aqueous NaOH solution by spreading a CoPc solution in CCl3COOH + CHCl3. This simple procedure allows a reproducible and homogeneous modification of the electrodes with a film thickness of the order of a monolayer. Cyclic voltammetry of the modified electrodes and UV-visible spectroscopy of the film and spreading solution is provided. Furthermore, silver electrodeposition on modified and unmodified glassy carbon electrodes from low-concentrated silver solutions in NaCl was studied, using relatively long deposition times up to 100 a at an overpotential of -0.3 V. The charge corresponding to the deposited silver was measured by anodic linear sweep voltammetry. Far both electrodes, linear plots of Q(2/3) vs. t were obtained, which is according to an instantaneous nucleation and three-dimensional growth mechanism.