The invention relates to a process by which organosilicon compounds carrying sulfur-containing organic radicals can easily be prepared by reacting organosilicons of the general formulaR.sub.a (R.sup.1 O).sub.b R.sup.2.sub.c SiO.sub.(4-a-b-c)/2(I)in whichR can be identical or different and is a monovalent organic radical,R.sup.1 can be identical or different and is a hydrogen atom or a monovalent organic radical,R.sup.2 can be identical or different and is a radical --QX, where Q is a divalent hydrocarbon radical and X is a halogen atom,a is 0, 1, 2 or 3,b is 0, 1, 2 or 3 andc is 0, 1, 2 or 3,with the proviso that the organosilicon compound has at least one radical R.sup.2 per molecule and the sum of a, b and c is less than or equal to 4, with sulfite in the presence of water.