With the increasing interest in automated synthesis and screening protocols, solid supported chemistry and biochemistry have become attractive technologies. Furthermore, the use of enzymes in solid phase synthesis has opened the route to selective and mild processes. The efficiency of enzymes in transforming substrates that are bound on solid supports is strictly related to the availability of polymers endowed with specific properties, above all permeability to enzymes. This review describes how the recent developments of this rapidly evolving area have made possible novel challenging applications of enzymes in solid phase synthesis. (c) 2006 Society of Chemical Industry.