Highly accurate values of the adiabatic electron affinity (EA) of the ground state (X 2 Σ + ) of the BO molecule, and the dissociation energy (D 0 ) of the anion BO - (X 1 Σ + ), have been determined using the CCSD(T) approach in conjunction with a series of doubly augmented correlation consistent basis sets, d-aug-cc-pVnZ, n=3-6. In addition, the full potential energy curve of BO - (X 1 Σ + ) has been constructed at the multireference configuration interaction, n=5 level. Our final values are, EA(BO)=2.50eV and D 0 (BO - )=215.7kcal/mol, in excellent agreement with experimental results.