Randomly excited structures are exposed to random stress loads that can result in fatigue failure. Prediction of such failure requires good structural dynamics and fatigue models. This study researches the multiaxial criteria which reduce the multiaxial stress state to an equivalent uniaxial stress. Several frequency-domain criteria can be found in literature. However, experimental comparison studies are scarce. This research presents and then theoretically and experimentally compares selected frequency-domain multiaxial criteria, namely: maximum normal stress, maximum shear stress and the C-S criterion. Time-to-failure results are compared across multiaxial criteria and with experimental data. Results show that selected methods give reliable estimates.