Electron attachment to Br2and HBr has been studied over a range ofE/Pvalues using a high‐pressure electron‐beam‐sustained gas‐discharge apparatus. Experiments were performed in gas mixtures containing the attaching species and a large excess (⩾99%) of N2which was included to control the electron temperature. Values of the dissociative attachment rate constants at an average electron energy near 1.0 eV for Br2and HBr were found to be 1.0×10−10and 8×10−10cm3/sec, respectively. Using the known electron energy dependence of the dissociative attachment cross section, the magnitude of the dissociative attachment cross section for HBr was estimated.