In the last 15 years aqueous organometallic chemistry and catalysis has emerged from being a laboratory curiosity to become an established field of research. Topics reviewed here include mechanistic studies on the effect of water on catalyzed reactions, the preparation of water soluble phosphines as ligands for catalysis, metal catalyzed organic reactions in water (hydrogenation, hydroformylation, carbonylation, olefin metathesis, hydrophosphination, etc.), chiral ligands and enantioselective catalysis, organometallic radical photochemistry in aqueous solutions, bioorganometallic chemistry,...