This paper describes techniques for marking both microelectrode tracks and exact recording loci using a combination of fast green dye and horseradish peroxidase (HRP). The procedure involves coating the exterior of HRP filled microelectrodes with fast green dye in order to identify electrode tracks, and ejecting HRP from the electrode to mark recording loci. Rapid, multiple marks can be made with this technique without harming the recording capabilities of the micropipette.