A process for preparing perfluoropolyoxyalkylenes with hydroxyl end groups having structure: T1—CFW1—O—Rf—CFW2—T2  (I) wherein: T1, T2, are selected from —CH2OH, —F, —CF3, —CF2CF3 with the proviso that at least one of T1 and T2 is —CH2OH; W1 and W2 are selected from F, CF3; Rf is a perfluoropolyoxyalkylene chain having a number average molecular weight 500-10,000 comprising one or more units of the type —CF2CF2O—, —CF2O—, —C3F6O—, —CF2(CF2)zCF2O— (z=1,2); —CR4R5CF2CF2O— with R4 and R5 selected from H, Cl, perfluoroalkyl group; said process comprising the following steps: a) adding an ester precursor having structure (I) and T1, T2 end groups selected from —F, —CF3, —CF2CF3, —COOR (R=linear or branched alkyl group having a number of C atoms from 1 to 5), with the proviso that at least one of T1 and T2 is —COOR, in a reaction mixture formed by: an inert or protic reaction solvent; a reducing agent selected from metal hydrides; an unreactive organic base with respect to the ester; b) hydrolysis of the product obtained in step a) for obtaining the compounds of structure (I) with at least a —CH2OH end group.