Aqueous dispersions of organopolysiloxanes are prepared by (a) reacting organopolysiloxanes having condensable groups with silanes: (R.sup.3O).sub.3SiCR.sup.2.sub.2--Y (II) or their hydrolyzates, where R.sup.2 is hydrogen or a monovalent C.sub.1-4 alkyl radical, R.sup.3 is a C.sub.1-8 alkyl radical, and Y is --CH.sub.2NHR.sup.4, --CH.sub.2NR.sup.4.sub.2 or in the presence of water and emulsifier, (b) adding an aqueous silica dispersion, optionally mixed with a silane of the formula (II), (c) optionally adding an adhesion promoter, and (d) optionally adding of further materials which do not take part in reaction (a), with the proviso that no metal-containing catalysts are used and that the organopolysiloxanes and silanes are used in such amounts that the organopolysiloxanes form elastomeric films insoluble in toluene on removal of water.