In an aqueous acidic plating bath for the electrolytic deposition of zinc, which contains conventional conductive salts, brighteners and surfactants, one of the surfactants is a surfactant of the formula I ##STR1## where R.sup.1 is C.sub.4 -C.sub.20 -alkyl, R.sup.2 is identical to R.sup.1 or is hydrogen, X and Y are each a radical --SO.sub.3 H, where the hydrogen atom can be replaced by an alkali metal or alkaline earth metal atom or by one equivalent of zinc and n is an integer from 5 to 50.