Gold monosulfide, AuS, has been detected and characterized in the gas phase using optical spectroscopy. The symmetries of the ground and low-lying electronic excited states have been determined by application of a synergy of hot and cold laser excitation techniques. The electronic spectra are assigned to progressions in four band systems associated with excitations from the X-2 Pi(1) ((2 alpha)(2)(2 pi)(3)) ground state to the A(2)Sigma(+) state arising from the (2 sigma)(1)(2 pi)(4) configuration and to the a(4)Sigma(-), B-2 Sigma(-), and C-2 Delta(i) states arising from the (2 sigma)(2)(2 pi)(2)(3 sigma*)(1) configuration. The bond length and dissociation energy of the ground X-2 Pi(1), state are determined to be 2.156(2) angstrom and 298 +/- 2 kJ/mol, respectively. A molecular orbital correlation diagram is used to rationalize the energy ordering of the excited states and the associated harmonic frequencies.