The use of water-soluble catalysts is under-going a very rapid growth. Such complexes allow an easy separation of the catalyst from the products of the reaction. An industrial implication is the hydroformylation process developed by Ruhr-Chemie with an annual production of 300 000 tons of butyraldehyde. This methodology, first developed in hydrogenation and hydroformylation, has been extended in palladium chemistry, mainly alkylation reaction via π-allyl intermediate. Heck and coupling reactions. The use of chiral water-soluble ligand allows the hydrogenation of prochiral substrates in a two-phase system or in water. In the future, the application of such catalysis will become a high priority, mainly due to the use of cheap and environmentally friendly solvent, water.