A process for separating bifunctional perfluoropolyethers (PFPEs) having two terminations —CH2OH from their mixtures with monofunctional PFPEs with one termination —CH2OH, of general formula X1—O—Rf—Y   (I) wherein Rf is a perfluoropolyoxyalkylene chain having a number average molecular weight of 500-10,000; X1 and Y are end groups selected from —CFXCH2OH (wherein X is F or CF3), —CF3, —CF2Cl, —CF2CF2Cl, —C3F6Cl, —CF2Br, —CF2CF3, wherein at least one of the two end groups is —CFXCH2OH, said process comprising the steps of: a) addition of the PFPE mixture to an adsorbing solid phase, under stirring; b) filtration of the mixture obtained in a): c) addition to the solid phase filtered in b), of a PFPE mixture having an average functionality higher than that of the PFPE mixture of the liquid filtered in b); c2) filtration of the mixture obtained in c); and subsequent treatment of the solid phase separated in c2) with a polar solvent obtaining a liquid containing the PFPE having high functionality.