Detailed structures of the etch pits on the (1 0 0) (0 1 0) and (0 0 1) surfaces of LiAlO2 single crystals have been studied The crystal was grown by the Czochralski-pulling technique Hot water is found to be a good etching solution for LiAlO2 crystal On the (1 0 0) surface many shallow rhomboidal etch pits with a deep rhombic pit at the center are revealed and can line up to form boundaries These etch pits are categorized into two groups which are symmetric relative to the [0 1 0] direction and are separated by boundaries made up of dense etch pits On the (0 0 1) surface square pyramid-like etch pits are present However rectangle-like etch pits are found on the (0 1 0) surface which may not be related to dislocations The density and the distribution of dislocations are studied A scheme of the domain structure is proposed to explain the observed shapes and distributions of etch pits (C) 2010 Elsevier B V All rights reserved