We prepared a novel series of water-soluble silicone-modified polyesters [poly(ethylene glycol) (PEG)silicone polyesters] by reacting organopolysiloxane with a hydroxy-terminated polyester. The polyesters were obtained by the polymerization of maleic anhydride and PEGs (molecular weights = 2000, 4000, 6000, 8000, and 10000). These water-soluble PEG-silicone polyesters can be used as auxiliaries in dyeing process because they exhibit good surface activities such as surface tension, low foaming, and wetting power. The presence of these surfactants also retarded the rate of nylon dyeing with acid dyes. The retarding effect and low-foaming property of these novel PEG-silicone polyesters make it possible for these surfactants to be used as leveling agents for modern nylon dyeing with acid dyes.