Abstract: Method of continuously casting steel slabs and the like wherein a layer of melting powder is maintained at the top portion of the casting mold with sufficient thickness so as to provide an increased thermal insulation to the liquid layers of steel and slag, whereby the formation of a solidified slag rim in the mold is eliminated and the surface quality of the steel products is considerably improved. The melting powder addition according to the invention also reduces the number of break-outs and consequently considerably increases the availability and productivity of the caster.