A theoretical study of molecular, electronic, and vibrational properties of the first excited state of the phenoxyl radical, A B-2(2), is presented. The calculated molecular geometries, vertical and adiabatic excitation energies, and harmonic vibrational frequencies are compared with analogous results obtained for the ground state. The calculated excitation energies correspond well to experimental data. The harmonic vibrational frequencies of the A B-2(2) and the ground state are similar except for modes involving the vibrations of the CO bond.