Highly boron-doped diamond (BDD) electrode films grown on silicon substrates were used to develop calibration curves for the detection of mercury. Anodic differential pulse voltammetlic technique was used for detecting ppb level concentrations of Hg. A comparison with glassy carbon (GC) indicates the extremely low background current and high sensitivity for the BDD electrodes. Further, the presence of ionic species such as chloride and nitrate also influence the sensitivity. Presence of chloride ions improves the sensitivity more than nitrates ions but the formation of mercurous chloride was found to be detrimental to further measurements. We have found that the sensitivity and reproducibility can be improved by co-depositing ppm amounts of gold on the BDD electrodes. (C) 2004 Elsevier B.V. All rights reserved.