The present invention relates to cosmetic cleaning agents containing surface-active betaines of the formula. ##STR1## wherein R.sup.1 and R.sup.2 are aliphatic hydrocarbon radicals having 1 to 18 carbon atoms and/or hydrogen and the sum of the carbon atoms in R.sup.1 and R.sup.2 is 9 to 18; R.sup.3 and R.sup.4 are the same or different and are lower alkyl or alkylol groups having 1 to 4 carbon atoms, x is an integer of 2 to 4, y is either 0 or 1, and z is an integer of 1 to 4; as well as their application as cleaning agents, for example, in hair washing and bathing preparations.