A process for the spin-finishing of a fiber, comprising the step of applying to the fiber a compound of the formula HO(CH2 CH2 O)x --RO--(CH2 CH2 O)y H in which R is an alkylene radical which is mono- or polysubstituted by alkyl, has 2 to 4 carbon atoms in the alkylene chain and contains methyl, ethyl, or propyl or isopropyl as the alkyl substituent, and the sum of x and y is 10 to 20, x and y bei