Synthetic rubber dispersions containing carboxyl groups, free from specks and with little tendency to foaming, with advantages for their technical application contain a copolymer of 0.3 to 1.0 parts by weight of itaconic acid and 99.0 to 99.7 parts by weight of a mixture of 10 to 90 parts by weight of one or more acyclic conjugated dienes having 4 to 9 carbon atoms and 10 to 90 parts by weight of one or more aryl vinyl monomers having 8 to 12 carbon atoms and/or (meth)acrylonitrile, in which the quantity of (meth)acrylonitrile is at most 50 parts by weight and wherein up to 25 parts by weight of the non-dissociating monomers may optionally be replaced by one or more other non-dissociating copolymerizable monomers, which dispersions are stabilized with 0.05 to 0.5% by weight, based on the copolymer, of an anionic emulsifier.