Aqueous dispersions of water-soluble polymers of N-vinylcarboxamides contain, based on 100 parts of water, (A) from 5 to 80 parts by weight of water-soluble polymer containing N-vinylformamide units and/or N-vinylacetamide units and having particle sizes of from 50 nm to 2 .mu.m and (B) from 1 to 50 parts by weight of at least one polymeric dispersant which is incompatible with the water-soluble polymers (A) in aqueous solution, which dispersions are prepared by polymerizing (A) from 5 to 80 parts by weight of N-vinylformamide and/or N-vinylacetamide, if desired together with other monoethylenically unsaturated monomers which form water-soluble polymers therewith, and (B) from 1 to 50 parts by weight of at least one polymeric dispersant which is incompatible with the polymers, formed from the monomers (A), in aqueous solution, in 100 parts by weight of water, at from 30 to 95.degree. C. in the presence of from 0.001 to 5.0% by weight, based on the monomers used, and the aqueous dispersions of water-soluble polymers are used as drainage aids, flocculants and retention aids and as wet and dry strength agents and as fixing compositions in papermaking.