Electrochemical studies on solution cast fullerene (C-60, C-70) films were carried out in aqueous solutions. It was observed that a special pretreatment of films in quinhydrone solution could provide suitable conditions to investigate the electrochemical behavior of fullerene films exclusively. It was found that fullerene films can conduct electrons to the solution phase in their partially reduced forms. They behave as diodes with pronounced current rectifying character. Results on these partially reduced layers also support conclusions on the bulk reduction of the fullerene films in aqueous media. (C) 1998 Elsevier Science Ltd. All rights reserved.