Abstract: Organopolysiloxanes are described with the same or different units of the formula:(O.sub.3/2 Si-R.sup.1 -SO.sub.3.sup.-).sub.x M.sup.x+ (1)in which R.sup.1 is alkyl, x is dependent on M and signifies a number from 1 to 4 and M represents hydrogen or a mono- to tetravalent metal ion and the valences of the oxygen atoms are saturated by silicon atoms of other groups of the formula (1), optionally by inserting cross-linking silicon, titanium or aluminum compounds and/or by di-, tri- and tetrasulfide units of the formula: ##STR1## in which the substituents R.sup.1 have the same meaning as in (1) and can be the same or different, wherein the ratio of the sum of silicon atoms in (1) and (2) to the silicon, titanium and aluminum atoms of the cross-linking agent ranges from 1:0 to 1:10. Furthermore, the method of obtaining the organopolysiloxanes containing sulphonate groups and the use thereof as strongly acidic cation exchangers are described.