Potassium bromate is a well-known dough conditioner that has been used for many years in breadmaking around the world. Published results of animal tests, however, have linked potassium bromate with renal cancer in rats. Recently, an analytical method has been developed to provide accurate and precise measurement of potassium bromate residues in bread. This method, which utilizes ion-pairing reverse-phase chromatography and post-column derivatization, can detect potassium bromate residues at levels as low as 0.5 ppb. This HPLC method was used to determine the effects of reducing agents and baking conditions on potassium bromate residues in two types of bread. No residual potassium bromate was detected in pullman-type breads with potassium bromate added at <15 mg/kg of flour. Residual potassium bromate was detected in open top-type bread with potassium bromate added at >9 mg/kg of flour. The distribution of residual potassium bromate in open top-type bread was localized in the top region of crust that rises out of the baking pan. Residual potassium bromate was not detected in bread made from the same dough formula when baked with a cover on the baking pan. Adding reducing agents such as L-ascorbic acid and/or ferrous sulfate had a significant effect on potassium bromate residues, reducing or eliminating them.