A technique for making recording microelectrodes containing an ultrafine carbon fibre is described. This technique can be used for single- and multi-barrel microelectrodes. These microelectrodes not only have a very low signal-to-noise ratio comparable with that found in tungsten microelectrodes but are simpler to make. When used in a multi-barrel array for iontophoretic application of drugs the carbon fibre microelectrode has many advantages over a fluid electrolyte-filled recording barrel, including very high signal-to-noise ratio and relative immunity to spike distortion during application of iontophoretic current.