A disclination model for grain subdivision is incorporated into the visco-plastic self-consistent (VPSC) polycrystal model and used to simulate the grain refinement during equal-channel angular pressing (ECAP). Strain incompatibilities between a homogeneous effective medium and a probe grain calculated by VPSC are assumed to result in an accumulation of disclinations at the grain junctions. The stresses of these disclinations are then relaxed by the growth of low-angle dislocation boundaries from the junctions. These boundaries split the grain into smaller, misoriented subgrains which, with further deformation, can lead to its subdivision into new grains. The applied ECAP deformation histories are given by simple shear and an analytical fan model. The corresponding evolutions of microstructure and texture during different ECAP routes are simulated. The calculated texture and intragrain misorientations evolutions are found to be in good agreement with available experimental data.