An amphiphilic C-60 tetracarboxylic acid (1) and its tetramethyl eater (2) have been prepared. They form stable Langmuir monolayer at the air-water interface, which can be deposited on semiconducting transparent ITO electrodes. The photoelectric responses of the monolayer-modified electrodes are measured in a conventional photoelectrochemical cell. The anodic photocurrent observed corresponds to an electron transfer from the electrolyte through LB film to the electrode. The action spectrum of the photocurrent is in good agreement with the absorption spectrum of the modified ITO electrode, confirming that the excited C-60 derivatives act as the photoactive species in the photoinduced electron transfer process. Factors influencing the photocurrent have been studied such as the intensity of the irradiation, concentration of redox agent in the electrolyte solution, bias voltage and pH.