Structural analysis of electrically poled samples of polycrystalline, (1-x)Bi(Mg1/2Zr1/2)O-3-xPbTiO(3) piezoceramics across morphotropic phase boundary reveals electric field-induced cubic to tetragonal phase transition and significant domain reorientation in tetragonal and two-phase compositions. The c-axis domain elongation is observed for tetragonal compositions after poling. The morphotropic phase boundary composition, having coexisting cubic and tetragonal phases in the unpoled state, exhibits alteration in relative proportion of the two phases, in addition to domain extension and reorientation along c-axis. For the morphotropic phase boundary composition, the tetragonality (c/a) is enhanced with significantly large c-axis strain (similar to 0.92%) in tetragonal phase after poling. Origin of ferroelectric P-E loop in cubic compositions is linked with the electric field-induced phase transition.