Process for the selective recovery of rare earth metals, nickel, cobalt, manganese and iron present in an Ni-MH battery, comprising the following steps: a) grinding of the battery, b) removal of the potassium hydroxide present in the ground battery obtained in step a) by washing with water, c) separation of the aqueous phase containing the potassium hydroxide by filtration and recovery, on the one hand, of a solid phase, and, on the other hand, of the aqueous phase, d) grinding of the solid phase obtained, e) separation of the ground parts of the solid phase having a greatest dimension of less than 1 mm and recovery of this solid phase having a greatest dimension of less than 1 mm, this phase being known as "black mass", f) dissolution of the obtained "black mass" in an acid, g) removal of the residual particles of carbon and/or of polymers, h) oxidation of the iron of state of oxidation +2 present in the solution obtained after steps f) and g) to give iron of state of oxidation +3, i) precipitation of the iron of state of oxidation +3 by adjustment of the pH of the solution in which it is present to 3.5, j) separation and washing of the precipitate obtained in step i), k) adjustment to 1 of the pH of the solution obtained after step j), l) addition of NaClO to the solution obtained in step k) in order to form an MnO 2 precipitate, m) separation and washing of the MnO 2 precipitate, n) adjustment to 3 of the pH of the solution obtained after step m), o) addition of NaClO to the solution obtained in step n) in order to form a Co 2 O 3.3H 2 O precipitate, p) separation and washing of the Co 2 O 3.3H 2 O precipitate formed in step o), q) adjustment to 1 of the pH of the solution obtained in step p), r) addition of oxalic acid to the solution obtained in step q) in order to precipitate the rare earth metals in the oxalate form, s) separation of the precipitate formed in step r), t) adjustment of the pH of the solution obtained after step s) in order to form an Ni 2 precipitate, and u) separation of the precipitate obtained in step t). a) grinding of the battery, b) removal of the potassium hydroxide present in the ground battery obtained in step a) by washing with water, c) separation of the aqueous phase containing the potassium hydroxide by filtration and recovery, on the one hand, of a solid phase, and, on the other hand, of the aqueous phase, d) grinding of the solid phase obtained, e) separation of the ground parts of the solid phase having a greatest dimension of less than 1 mm and recovery of this solid phase having a greatest dimension of less than 1 mm, this phase being known as "black mass", f) dissolution of the obtained "black mass" in an acid, g) removal of the residual particles of carbon and/or of polymers, h) oxidation of the iron of state of oxidation +2 present in the solution obtained after steps f) and g) to give iron of state of oxidation +3, i) precipitation of the iron of state of oxidation +3 by adjustment of the pH of the solution in which it is present to 3.5, j) separation and washing of the precipitate obtained in step i), k) adjustment to 1 of the pH of the solution obtained after step j), l) addition of NaClO to the solution obtained in step k) in order to form an MnO 2 precipitate, m) separation and washing of the MnO 2 precipitate, n) adjustment to 3 of the pH of the solution obtained after step m), o) addition of NaClO to the solution obtained in step n) in order to form a Co 2 O 3.3H 2 O precipitate, p) separation and washing of the Co 2 O 3.3H 2 O precipitate formed in step o), q) adjustment to 1 of the pH of the solution obtained in step p), r) addition of oxalic acid to the solution obtained in step q) in order to precipitate the rare earth metals in the oxalate form, s) separation of the precipitate formed in step r), t) adjustment of the pH of the solution obtained after step s) in order to form an Ni 2 precipitate, and u) separation of the precipitate obtained in step t).