In the present work we study the performance of orbitals from an effective exact exchange-only optimized potential method, the localized Hartree-Fock approach, in multireference ab initio methods. In the first part local Hartree-Fock orbitals are used to describe the excited states of carbon monoxide, formaldehyde, and acetone in multireference configuration interaction calculations. The local Hartree-Fock orbitals are compared with standard Hartree-Fock orbitals, and those from a gradient corrected and a hybrid density functional. This part mainly tries to analyze possible deficiencies of the local Hartree-Fock orbitals. In the second part of this work the above-mentioned orbitals are tested in multireference perturbation theory second-order. We test to which extent known deficiencies of single state perturbation theory second-order are eliminated in multireference approaches, and then study how well local Hartree-Fock orbitals perform in multireference perturbation theory second-order computations of excited states. (C) 2003 American Institute of Physics.