The physics program at the HERA electron-proton colliding beams facility covers a wide range of processes. Since the start up of HERA, both the ZEUS and the H1 experiments have produced a wealth of results on deep inelastic scattering, photo production and on diffractive processes. In addition they have searched for signals indicating New Physics. In this seminar, recent results from the ZEUS experiment on
hard scale processes are presented. They include: neutral and charged current deep inelastic scattering cross sections, measured in positron-proton and electron-proton scattering up to very high momentum transfers; measurements of the structure function F2 of the proton over a large kinematic range and the confrontation of these
data to QCD predictions; a selection of other QCD measurements performed in both deep inelastic scattering and photo production.