Abstract: The method of manufacturing nickel hypophosphite from a solution of hexahydrated nickel sulfate and a solution of monohydrated sodium hypophosphite by an electro-membrane technique, consists: a) in introducing respectively the hexahydrated nickel sulfate solution and the monohydrated sodium hypophosphite solution into each of two dilution circuits of four-compartment electrodialysis cells formed by alternating stacks of cationic and anionic homopolar membranes in an electrodialysis apparatus having an anode and a cathode that are insoluble; b) in applying an electrical current from the anode to the cathode without regulating the pH of the solutions contained in the dilution and concentration circuits but regulating the electricity supply, either in voltage or in current; and c) in recovering a hexahydrated nickel hypophosphite solution from one of the concentration circuits.