A liquid membrane electrode, which responds to bromide ions is described. It is based on the use of the bis(4-hydroxyphenyl) 1,4-diaza-1,3-butadiene-Hg(II) complex as the electroactive species. The electrode response is Nernstian over the concentration range 10−5–10−1 M of bromide. The sensitivity of the electrode is high enough to permit the accurate determination of a little as 0.4 µg/mL of bromide without any significant interference from high levels of common anions including chloride, iodide, nitrate, and sulfate. The potentiometric selectivity coefficient data display negligible interference from 12 different organic and inorganic anions. The electrode has a fast response time (<20 s), good slope stability over the pH range 4–9.5 for a period of at least two months and can be used for direct potentiometric determination of hyoscine bromide. The sensor was also used as an indicator electrode in the potentiometric titration of the bromide with Ag+ ions.