The erosion of an axial fan was investigated, both theoretically and experimentally. A computer program was developed to predict particle trajectories and erosion through turbomachines. It also accounts for different boundary conditions and stage interfaces. The governing equations of the particle motion were solved using Runge-Kutta Fehlberg technique in a given flowfield. The tracking of particles and their locations are based on the finite element interpolation method. The methodology was applied to an axial fan with inlet guide vanes (IGV). The flowfield was solved using the TASCflow code. The number of particles seeded upstream of the IGV was determined from experimentally measured profile concentration, with respect to a random distribution of particle sizes. The erosion of the blades and changes to the chord and tip clearances were also measured. The concentration profiles and velocities of the particle were measured with a laser transit anemometer and used as input to the trajectory code. The fan performance was measured before and after sand ingestion to assess the degradation in performance due to the eroded geometry