Where bromide ion is found in water used as a source of drinking water, and chlorination is used for disinfection, bromide ion is oxidized to bromine and can result in the formation of organic bromine compounds. There are presently no treatment techniques available for economic removal of bromide ion. A potential treatment strategy is to use an alternative oxidant; ozone is one such alternative. This review presents the reactions of ozone and bromide ion. Understanding of these reactions leads to possible treatment strategies when ozone is used, in the presence of bromide ion, to minimize the formation of trihalomethanes.