A process for the hydrogenation of an oxime of formula to produce a hydroxylamine salt of formula by reacting oxime with hydrogen in the presence of an iridium catalyst of formula (Illa) or formula (Illb) and an acid; wherein R 1, R 2 and R 3 are each independently hydrogen, C 1 -C 8 alkyl, C 1 -C 8 hydroxyalkyl, C 1 -C 8 cyanoalkyl, C 1 -C 6 alkoxyC 1 -C 8 alkyl, di(C 1 -C 6 alkoxy)C 1 -C 8 alkyl, C 1 -C 8 haloalkyl, C 2 -C 6 alkenyl, C 3 -C 8 cycloalkyl, phenyl, phenylC 1 -C 3 alkyl or heteroaryl, and wherein the cycloalkyl and phenyl moieties are each optionally substituted with 1 to 5 groups selected from hydroxyl, halogen, C 1 -C 6 alkyl, C 3 -C 8 cycloalkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, phenyl, heteroaryl, C 1 -C 6 alkoxycarbonyl, acylamino, amido, cyano, nitro and C 2 -C 6 alkenyl; or R 1 and R 2 together with the carbon atom to which they are attached may form a 4- to 8-membered saturated cycloalkyl or heterocyclyl ring, wherein the heterocyclic moiety is a non-aromatic monocyclic ring which comprises 1, 2 or 3 heteroatoms, wherein the heteroatoms are individually selected from N, O and S; R 6, R 7, R 8, R 9 and R 10 are each independently hydrogen or C 1 -C 3 alkyl; represents a bidentate chelating ligand comprising at least one carbon atom which coordinates to iridium and at least one nitrogen atom which coordinates to iridium; X represents an anionic group of the formula R 14 -SO 2 O- or R 15 -C O-, wherein R 14 is hydroxy, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, or phenyl, wherein the phenyl moieties are optionally substituted by 1, 2, 3 or 4 substituents, which may be the same or different, selected from R 16; R 16 is C 1-4 alkyl, C 1-4 haloalkyl, nitro, or halogen; R 15 is C 1-6 haloalkyl or phenyl, wherein the phenyl moieties are optionally substituted by 1, 2, 3 or 4 substituents, which may be the same or different, selected from R 17; R 17 is C 1-4 alkyl, C 1-4 haloalkyl, nitro or halogen; Y represents a neutral ligand; and Z represents an anionic group. wherein R 1, R 2 and R 3 are each independently hydrogen, C 1 -C 8 alkyl, C 1 -C 8 hydroxyalkyl, C 1 -C 8 cyanoalkyl, C 1 -C 6 alkoxyC 1 -C 8 alkyl, di(C 1 -C 6 alkoxy)C 1 -C 8 alkyl, C 1 -C 8 haloalkyl, C 2 -C 6 alkenyl, C 3 -C 8 cycloalkyl, phenyl, phenylC 1 -C 3 alkyl or heteroaryl, and wherein the cycloalkyl and phenyl moieties are each optionally substituted with 1 to 5 groups selected from hydroxyl, halogen, C 1 -C 6 alkyl, C 3 -C 8 cycloalkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, phenyl, heteroaryl, C 1 -C 6 alkoxycarbonyl, acylamino, amido, cyano, nitro and C 2 -C 6 alkenyl; or R 1 and R 2 together with the carbon atom to which they are attached may form a 4- to 8-membered saturated cycloalkyl or heterocyclyl ring, wherein the heterocyclic moiety is a non-aromatic monocyclic ring which comprises 1, 2 or 3 heteroatoms, wherein the heteroatoms are individually selected from N, O and S; R 6, R 7, R 8, R 9 and R 10 are each independently hydrogen or C 1 -C 3 alkyl; represents a bidentate chelating ligand comprising at least one carbon atom which coordinates to iridium and at least one nitrogen atom which coordinates to iridium; X represents an anionic group of the formula R 14 -SO 2 O- or R 15 -C O-, wherein R 14 is hydroxy, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, or phenyl, wherein the phenyl moieties are optionally substituted by 1, 2, 3 or 4 substituents, which may be the same or different, selected from R 16; R 16 is C 1-4 alkyl, C 1-4 haloalkyl, nitro, or halogen; R 15 is C 1-6 haloalkyl or phenyl, wherein the phenyl moieties are optionally substituted by 1, 2, 3 or 4 substituents, which may be the same or different, selected from R 17; R 17 is C 1-4 alkyl, C 1-4 haloalkyl, nitro or halogen; Y represents a neutral ligand; and Z represents an anionic group.