The evolution of the structure of aluminum alloy 2219 ingot during equal channel angular pressing (ECAP) to a cumulative strain of e = 12 at 475 °C (~0.8Tm) was studied. It was found that the structural changes during hot ECAP were determined by the action of two main structural processes. In the early stages of ECAP (e = 1–3), the alignment of the initial grains in the pressing direction was mainly accompanied by the formation of a dynamically equilibrated subgrain structure. However, upon reaching a critical strain (e ≈ 3–4), grain fragmentation by deformation/microshear bands started with a subsequent gradual increase in the number of bands and their misorientation, leading to grain refinement. As a result, a heterogeneous bimodal grain structure was formed after e = 12, consisting of about 50 % new grains of about 10 μm size and residual fragments of the initial grains containing subgrains. It was concluded that grain refinement during hot ECAP occurred by the mechanism of continuous dynamic recrystallization.