In studies of radiation effects on materials for reactor applications, it is desirable to identify irradiation methods that induce microstructural effects similar to those of neutrons, but at reduced time and expense. In the present study, 2 MeV protons were used to introduce up to seven displacements per atom in Zircaloy 4 at 350°C. The effect on the intermetallic precipitates, the formation of dislocation loops and hardness were investigated by analytical and high-resolution transmission electron microscopy (TEM). In addition, the precipitate evolution during 600 keV Ne ion irradiation at 350°C was monitored by in situ TEM. The results are compared with literature data for neutron-irradiated Zircaloy. While Ne irradiation leads to precipitate amorphization, no amorphization or chemical redistribution is observed in the proton irradiated sample. The dislocation-loop size and density in the Zr matrix of the proton-irradiated alloy are similar to those in the neutron-irradiated alloys.