A method for the manufacture of a thin-film field-effect device comprising, on a mechanical support layer, source and drain electrodes (S, D), a layer of semiconductor material (SC) for the formation of a conduction channel, and a gate electrode (G) insulated from the channel region, is described. The method provides for the use of a mechanical support layer in the form of a film (INS) of flexible, electrically insulating material; for the formation of the source and drain electrodes (S, D) in accordance with a predetermined configuration on a first surface of the insulating film; and for the formation of the gate electrode (G) on the opposite surface of the insulating film (INS) in accordance with a predetermined configuration complementary with the configuration of the source and drain electrodes (S, D), that configuration being achieved by a lithographic technique by selective masking determined by the source and drain electrodes (S, D) which are formed on the first surface of the film (INS).