During laser surface remelting, thermal expansion in heating and contraction of material in cooling and due to microstructure changes in the heated surface layer, the thin flat specimen deforms. This induces volume changes during the remelting of the thin surface layer and causes internal stresses. By measuring the deformation of the flat specimen during the remelting process as well as after the laser beam interaction, i.e, to the moment when the specimen cools down to the ambient temperature, it is possible to follow the progress of specimen deformation. New experimental technique for measuring deformation during laser surface remelting on thin flat specimen from nodular iron 500-7 was applied. Optimal laser remelting conditions were chosen, while the way of guiding the laser beam over the surface of flat samples and degree of defocusing were varied.