A process for the manufacture of a perfluorooxycarboxylate of formula (I): R
f
O—CF
2
CF
2
—O—CF
2
—COOX
a
(I), wherein R
f
is a perfluoro(oxy)alkyl group, and X
a
is H, a monovalent metal or an ammonium group of formula NR
N
4
, with R
N
, equal or different at each occurrence, being H or a C
1-6
hydrocarbon group, said process comprising: (A) reacting a perfluorovinylether of formula R
f
—O—CF═CF
2
with an ethylene glycol derivative selected among ethylene glycol (HO—CH
2
CH
2
—OH), glycolic acid (HO—CH
2
—COOH), glycolaldehyde (HO—CH
2
—CHO) and protected derivatives thereof, so as to yield the corresponding addition product of formula R
f
—O—CFH—CF
2
—O—CH
2
-E, and E being selected among —CH
2
OH, —COOH and —CHO; (B) optionally protecting functional group E with suitable chemistry; (C) fluorinating the (protected) addition product to yield the corresponding perfluorinated addition product; (D) optionally deprotecting the perfluorinated addition product to yield corresponding acyl fluoride of formula R
f
—O—CF
2
—CF
2
—O—CF
2
—C(O)F; and (E) hydrolyzing and, optionally, neutralizing, the acyl fluoride for yielding the perfluorooxycarboxylate of formula (I).