Electrochemistry of films made from cationic surfactant didodecyldimethylammonium bromide (DDAB) containing metallofullerene Gd@C-82 on a glassy carbon electrode was investigated in an aqueous solution, and both oxidation and reduction peaks of Gd@C-82/DDAB films were found in the potential range between 0.6 and -1.0 V vs. a saturated calomel electrode. Electrochemically stable metallofullerene modified electrodes were produced. Furthermore, electrocatalysis of myoglobin and cytochrome c at the Gd@C-82/DDAB films was also studied. (C) 2004 The Electrochemical Society.