The present invention relates to an acidic zinc or zinc-nickel alloy plating bath composition comprising a source for zinc ions, optionally a source for nickel ions, a source for chloride ions and at least one dithiocarbamyl alkyl sulfonic acid or salt thereof. Said plating bath composition and the corresponding plating method result in zinc or zinc-nickel alloy layers having an improved throwing power and thickness distribution, particularly when plating substrates having a complex shape and/or in rack-and-barrel plating.