The invention relates to alkyl ether carboxylic acid taurides of the formulaR.sup.2 --(OC.sub.2 H.sub.4).sub.n --O--CH.sub.2 --CO--NR.sup.1 --C.sub.2 H.sub.4 --SO.sub.3 M,in which n is greater than 0, R.sup.1 =H or C.sub.1 -C.sub.4 alkyl, R.sup.2 =C.sub.5 -C.sub.22 alkyl and M=H, Na, K, Ca/2 or Mg/2.Processes for their preparation and their use as surface-active substances, especially as mild cleaning agents for cosmetic purposes, are also described.