A disposable electrochemical sensor for the determination of heavy metal traces has been designed for environmental field analysis. The sensor is supported on a polycarbonate film and consists of an amperometric transducer in combination with an adjacent silver-ink reference electrode. The transducer itself is composed of a network of carbon disc microelectrodes. This array of microelectrodes covers a sensing area of 5 x 5 mm and is made up of some 1000-3000 electrodes. Individual disc microelectrodes measuring 15 mu m diameter, have a recessed geometry with hole depth of less than 10 mu m and centre-to-centre separation between 100 and 300 mu m. A novel three-stage fabrication process based on conventional thick-film printing techniques, vacuum polymerisation of a dielectric and a uv excimer laser photoablation process was used to pattern the disc array structure. This microfabrication method has been evaluated on a laboratory scale and batch production. Amperometric performance and structural characteristics of the electrochemical sensor have been examined by chronoamperometry and electron microscopy. Variations in the sensor current response were studied in order to reduce the diffusion shielding characteristics of individual discs. An optimal microelectrode spacing was assigned to the sensor of 160 mu m giving more than one thousand discs per device. The printed sensor is currently under development for single-use field measurements of heavy metals using potentiometric stripping analysis.