The invention provides a process for preparing arylpoly(oxalkyl)benzyl-dimethylammonium derivatives of the formula (1) which comprises reacting compounds of the formulae (2) and (3) where X=Br, Cl, R—SO3 with R=alkyl, alkylaryl R1=H, C1- to C16-alkyl or O—C1- to O—C16-alkyl in the ortho, meta or para position, R2=H, C1- to C4-alkyl or O—C1- to O—C4-alkyl, R3=H, C1- to C16-alkyl or O—C1- to O—C16-alkyl in the ortho, meta or para position, and n=1, 2, 3 or 4, at temperatures of from 60 to 160° C. in a solvent under the autogenous pressure.