Bromine dioxides OBrO and BrOO are theoretically studied by means of valence-only ab initio correlated calculations using TZ(2df) basis sets generated for O, Cl, and Br atoms, especially optimized for averaged relativistic effective core potentials (AREP). Equilibrium geometries for these dioxides are obtained using UMP2 and CCSD(T) electron correlation methods, while harmonic frequencies and dipole moments are computed at the UMP2/AREP/TZ(2df) level. The effect of spin contamination on UMP2 results for geometries and frequencies in these doublet radicals is also discussed. All the analyses dealing with energies are based on CCSD and CCSD(T) calculations. The energetic ordering of both bromine dioxides as well as the two possible dissociation channels, Br + O-2 and BrO + O, are discussed. The nature of the bonding in the energetically more stable BrOO isomer is also investigated by studying its energy surface; a small barrier between 1.2 and 1.7 kcal/mol for this dioxide dissociating into Br + O-2 is predicted.