Liquid sloshing is an important issue in transportation, aerospace and automotive. Effects of sloshing in a moving liquid container can cause issues in: vehicle stability, safety, component fatigue, audible noise and comfort issues, fill level indication, etc. The sloshing phenomenon is a highly non-linear oscillatory movement of the free-surface of liquid inside a container (tank) under the effect of continuous or momentarily excitation forces. These excitation forces can result from sudden acceleration, braking, sharp turning or pitching motions. Due to the fluid inertia, waves are generated inside the tank, which can generate high pressure gradients over the tank surface when the fluid impacts the surface, causing the tank to vibrate resulting in fatigue loads. Structural fatigue in land vehicles is a major concern for loads in the 2-200 Hz range, but especially at the lower frequencies. Also, for the dimensions associated with automotive, the fundamental frequency of the sloshing waves is usually a fraction of a Hertz, so frequencies above 2 Hz constitutes “high frequencies” for sloshing. Sloshing within fuel tanks causes rapid energy dissipation at the fluid resonant modes. Due to viscous effects (friction) the amplitude of the waves decreases over time when external excitation is stopped (fuel damping). The present work evaluates the fuel viscous damping through CFD at “high frequency” excitation conditions in automotive fuel tanks. These damping coefficients are important parameters for the accurate evaluation of the structural durability of fuel tank and its components. In order to evaluate fuel damping at high frequency sloshing conditions different fuel levels and fuel types were evaluated at different excitation frequencies within the 2-20 Hz range.