Chemical short-range ordering is an important structural feature that would significantly affect materials properties, including mechanical properties. Chemical short-range ordering has been discovered in many alloy systems and usually forms at high temperatures during the materials synthesis or thermal annealing processes. Here we report chemical short-range ordering in an ultrafine-grained supersaturated Al-Zn alloy introduced by severe plastic deformation (strain >1) at room temperature. The chemical short-range ordering results in an ordered L10-AlZn structure with the dimensions of 1–3 nm. It is believed that vacancies introduced by severe plastic deformation play an important role in the formation of the chemical short-range ordering at room temperature.