A method of finishing synthetic organic fibrous material, in particular of providing such material with an antistatic finish and simultaneously improving the dirt repellency is provided, which comprises treating said material with aqueous or organic solutions or emulsions which contain (a) at least one copolymer derived from at least two of the monomers of formulae ##STR1## wherein R is straight-chain or branched alkyl of 1 to 8 carbon atoms, R.sub.1 is hydrogen or methyl, R.sub.2 is alkyl of 1 to 6 carbon atoms, m is an integer from 6 to 15, and each of r and s is 1 or 2, or a copolymer of the above monomers and further ethylenically unsaturated monomers, optionally in admixture with further homo- or copolymers and/or monomeric compounds. The furnish synthetic organic fibrous material, especially textile material, shows a permanent antistatic effect. The antisoiling effect and also the fastness to rubbing and light and the soft handle are not impared by the finish.