The high enantio- and regiocontrol afforded by phosphinooxazoline ligands has fuelled research into their use for asymmetric hydrogenation. Iridium complexes incorporating phosphinooxazoline ligands have been shown to be effective for classic hydrogenation using H, with ruthenium and palladium catalysts having also been investigated for transfer hydrogenation. In addition to theoretical studies, the structural and kinetic properties of Ir-PHOX complexes have been investigated to better understand their behaviour as hydrogenation catalysts.