We report an improved approach for fabricating Ag/AgCl reference electrodes for use in Harned Cell measurements of pH. Standard fabrication procedures involve converting a proportion of Ag to AgCl. This is usually driven by applying a fixed current, instead the novel approach presented here uses a fixed potential. This has resulted in an ensemble of electrodes of superior repeatability. The transient current data provides an indication of the geometric surface area of each electrode, offering important information about the microstructure. This approach has far-reaching implications for improving the repeatability of Ag/AgCl electrodes and reducing uncertainty in pH measurement. (C) 2012 Elsevier Ltd. All rights reserved.