An approach to estimating pressure fields due to unsteady flows associated with flow- induced vibration is presented. Pressure estimates of this type are useful for modeling the hydrodynamic forces on structures undergoing flow-induced vibration (Paper F02). The approach is based on a boundary-element solution to the Poisson equation for total pressure, using measurements of both the velocity field and the motion of the structure as input. An outline of the problem formulation and numerical issues will be presented. An application of the method to the case of flow-induced vibration of a cantilevered cylinder will be presented. Measurements of the velocity field in a finite control volume containing the vibrating cylinder are used to estimate the pressure and pressure work both on the outer boundary of the control volume, as well as on the cylinder surface. Estimates of the hydrodynamic energy input to the cylinder are presented, with emphasis given to the separate contributions of cylinder motion and fluctuations of the wake.