A previously reported extension of the double many-body expansion formalism has been used to model the main features of the ground and excited (2)A " states of HO2. The approach uses accurate two-body extended Hartree-Fock approximate correlation energy curves, while introducing three-body effects through the dressing of the diatomic states that arise in the diatomics-in-molecules treatment of the potential matrix. Although minimal atomic basis sets have been employed, a correct description of the complete manifold of states has been obtained for the title system. Thus, the potential energy surfaces of the present work may be used for dynamics calculations, which would be valuable to test their reliability.