La(Mg1/2Ti1/2)O-3 ceramics were prepared using a conventional solid-state reaction route. X-ray diffraction analysis revealed that La(Mg1/2Ti1/2)O-3 possesses a distorted perovskite structure consisting of both in-phase and anti-phase tilting accompanied by anti-parallel shifting of La3+ cation. Superlattice reflections, indicative of 1:1-type ordering of Mg2+ and Ti4+ cations in the octahedral sites, were observed. The crystal symmetry was deduced to be monochnic with P2(1)/n space group (No. 14). Transmission electron microscopy analysis revealed two types of twin domains, classified according to the symmetry elements relating adjacent domains. Twin domains with specific orientations, related by mirror operations along {112} and (110) planes, were identified. La(Mg1/2Ti1/2)O-3 exhibited a high density of dislocations that interact with the twin boundaries resulting in incoherent twin interfaces. In addition, two morphologically distinct anti-phase domains were observed resulting from (i) off-center displacement of the La3+ cations, and (ii) 1:1 ordering of the B-site sublattice.