The 364 nm photoelectron spectra of AuO- and AuS- have been measured. The electron affinities of AuO and AuS have been determined to be 2.374 +/- 0.007 and 2.469 +/- 0.006 eV, respectively. The electronic ground states of the neutral diatomics are (2)Pi(i) states, and the spin-orbit splitting between the X(2)Pi(1/2) and (2)Pi(3/2) states is 1440 +/- 80 cm(-1) for AuO and 1280 +/- 60 cm(-1) for AuS. A 590 +/- 70 cm(-1) vibrational peak built off the (2)Pi(1/2) origin of the AuO spectrum is clearly detected, while the corresponding peak built off the (2)Pi(3/2) origin is barely detectable. The corresponding 400 +/- 30 cm(-1) vibration in the AuS spectrum shows the opposite behavior, with the (2)Pi(3/2) showing the stronger vibrational activity. Franck-Condon analyses of the spectra establish that the equilibrium bond length of X(1)Sigma(+)AuO(-) (AuS-) differs from the average bond length of the two spin-orbit states of AuO (AuS) by -0.015 +/- 0.008 Angstrom (+0.018 +/- 0.007 or +0.007 +/- 0.007 Angstrom). These bond length relations reflect different extent of relativistic effects between the anions and the neutrals. The intensity of the X(2)Pi(1/2) origin peak is significantly greater than that of the X(2)Pi(3/2) origin peak in both AuO and AuS. These features are the results of strong second-order spin-orbit coupling between the X(1)Sigma(+) state and A (3)Pi(0) state in the corresponding anions. The bond length of X(1)Sigma(+)AuO(-) has been determined to be 1.899 +/- 0.006 Angstrom based upon the bond length of X(2)Pi(3/2)AuO.