To provide a method of producing a polyoxyalkylene-modified polysiloxane composition that is free of acid-mediated carbon-oxygen bond and silicon-oxygen bond cleavage, that is substantially deodorized and also does not generate odor with elapsed time, and that is therefore well suited for use in cosmetic applications, e.g., for hair cosmetics, skin cosmetics, and so forth. A production method of this invention is characterized by removing the odor-causing substance from a polyoxyalkylene-modified polysiloxane composition that has been synthesized by a hydrosilylation reaction, by subjecting the polyoxyalkylene-modified polysiloxane composition to a hydrolysis treatment in the presence of an acidic inorganic salt that is a solid at 25° C. and gives a specific pH at 25° C. in aqueous solution; for example, potassium hydrogensulfate.