A validated finite element analysis is described for the upsetting of a cylindrical specimen between two parallel rigid dies, where the workpiece is exposed to kinematic and radial or longitudinal ultrasonic oscillatory loading conditions. Numerical results are presented to show the effects of variation in several parameters on the die-specimen interface for Plasticine, and how stress superposition, temperature and friction reduction contribute to the reduced deformation forces, for both radial and longitudinal die oscillation directions.