A bromide-mediated silver electrode was applied to the measurement of haemoglobin. Bromide ions showed very good redox behaviour with the silver electrode. The cathodic and anodic peak potentials were related to the concentration of bromide ions involved in making the bromide-modified silver electrode. The electrode reaction in the bromine solution was a diffusion-controlled process. In the presence of pure haemoglobin, the modified electrode showed positive shift in cathodic and anodic peaks: -170 to -140 mV for cathodic peak and +30 to +65 mV for anodic peak with a new pair of cathodic and anodic peaks appearing at -58 and 218 mV, which were related to haemoglobin. Redox peak currents increased linearly as haemoglobin concentrations increased from 5 to 70 microM. The correlation coefficient and detection limit were 0.997 and 2 microM respectively. For a real test sample, the correlation coefficient and detection limit of the experiment were 0.993 and 4 microM respectively. The relative S.D. of results was 2.8% for five successive determinations of 20 microM haemoglobin. The modified silver electrode showed very good repeatability and stability for the determination of haemoglobin.